CERNSeptember/October 2019 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the September/October 2019 issue of CERN Courier.

During the final decade of the 20th century, the Large Electron Positron collider (LEP) took a scalpel to the subatomic world. Its four experiments – ALEPH, DELPHI, L3 and OPAL – turned high-energy particle physics into a precision science, firmly establishing the existence of electroweak radiative corrections and constraining key Standard Model parameters. One of LEP’s most important legacies is more mundane: the 26.7 km-circumference tunnel that it bequeathed to the LHC. Today at CERN, 30 years after LEP’s first results, heavy machinery is once again carving out rock in the name of fundamental research. This month’s cover image captures major civil-engineering works that have been taking place at points 1 and 5 (ATLAS and CMS) of the LHC for the past year to create the additional tunnels, shafts and service halls required for the high-luminosity LHC. Particle physics doesn’t need new tunnels very often, and proposals for a 100 km circular collider to follow the LHC have attracted the interest of civil engineers around the world. The geological, environmental and civil-engineering studies undertaken during the past five years as part of CERN’s Future Circular Collider study, in addition to similar studies for a possible Compact Linear Collider up to 50 km long, demonstrate the state of the art in tunnel design and construction methods.

Also in this issue: a record field for an advanced niobium-tin accelerator dipole magnet; tensions in the Hubble constant; reports on EPS-HEP and other conferences; the ProtonMail success story; strengthening theoretical physics in DIGGING southeastern Europe; and much more. FOR To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier PHYSICS To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier Exploring LEP’s legacy Hubble constant questioned Accelerator magnet breaks record EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING

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IN THIS ISSUE V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / o c t o b e r 2 01 9 It’s Time for a New Generation Fermilab

of Power Solutions! NASA and ESA CERN-AC-9107004_2-1

FOR RESISTIVE AND SUPERCONDUCTING MAGNETS

CT-BOX Dipole development US researchers have set a record for Life at LEP Accelerator physicists Hubble discrepancy Nobel-laureate Adam All-In-One Current Measurement and Calibration System accelerator-magnet field strength. 7 combined acumen with grit at a collider Riess discusses the accelerating expansion of Up to ±1.000 A, 1 ppm/K TC, 100 ksps Data-Logger and Oscilloscope that transformed the field. 39 the universe. 47 CT-Viewer software included with Ethernet, Serial and USB NeWS people EASY-DRIVER ±5 A and ±10 A / ±20 V Bipolar Power Supply Series ANALYSIS ENERGY FRONTIERS FIELD NOTES CAREERS Record dipole field CMS revisits rare and EPS-HEP looks ahead From SUSY to the Full-Bipolar operation, Digital Control Loop, Ethernet Connectivity ProtonMail Device supported by Visual Easy-Driver software • Astroparticle-theory beautiful decays • Higgs hunting boardroom centre • Breakthrough • Bottomonium • Between desert and ProtonMail’s founders Prize for Supergravity elliptic-flow no-show swampland • Humboldt left academia with the FAST-PS-M • CERN and ESA join • ATLAS pursues Higgs Kolleg • Cold-atom goal of making e-mail Digital Monopolar Power Supplies - up to 100 A forces • MedAustron properties • LHCb interferometry • FCC account holders the High-Precision Monopolar Power Converters with Gigabit Ethernet • Galaxy simulation • chases charged-lepton week • Strangeness in client rather than the Embedded Linux OS, device supported by Visual PS software Cloud computing. 7 flavour violation.15 Quark Matter • Muon product. 53 g−2. 19 FAST-PS FeAtureS Digital Bipolar Power Supplies - up to ±30 A and ±80 V Full-Bipolar, Digital Control Loop, High-Bandwidth, 10/100/1000 Ethernet TUNNEL ENGINEERING LEP’S PHYSICS LEGACY THE STORY OF LEP Embedded Linux OS, device supported by Visual PS software Tunneling for LEP’s electroweak The greatest lepton physics leap collider The civil engineering 519-529 (1989) B231 30 years ago, ALEPH, Steve Myers tells LEP’s FAST-PS-1K5 underpinning proposals story from conception Digital Bipolar Power Supplies - up to ±100 A and ±100 V Phys.Lett. DELPHI, L3 and OPAL for a future collider. 26 embarked upon a physics to its emotional final 1.500 W, Paralleling via SFP/SFP+, 1 ppm/K TC, 10/100/1000 Ethernet M Br ice/CER N-PHO T O-201908-213-1 tour de force. 32 day. 39 Embedded Linux OS, device supported by Visual PS software

NGPS opINIoN DepArtmeNtSCERNSeptember/October 2019 cerncourier.com COURIERReporting on international high-energy physics High-Stability 10-kW Power Supply - 200 A / 50 V Digital Control Loop, Paralleling via SFP/SFP+, 10/100/1000 Ethernet VIEWPOINT INTERVIEW REVIEWS FROM THE EDITOR 5 Embedded Linux OS, device supported by Visual PS software Building Balkan Grappling with The cutting edge of NEWS DIGEST 13 bridges in theory dark energy cancer research APPOINTMENTS 56 European support is vital Adam Riess discusses The Physics of Cancer & AWARDS to build capacity in discrepancies in the CERN and the Higgs • RECRUITMENT 58 southeastern Europe. 45 Hubble constant. 47 Boson Subatomic On the cover: DIGGING • DEEP FOR Desire. 51 A road-header at point PHYSICS 5 in BACKGROUND 62

August,Exploring LEP’s legacy preparing for the Questioning Hubble’s constant high-luminosityAccelerator magnet breaks record LHC upgrade. (M Brice/CERN.) 26 www.caenels.com CERN COURIER SEPTEMBER/OCTOBER 2019 3

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Boring matters CERN-AC-8701958 u r i ng t he fi n a l de c ade of t he 20t h ce nt u r y, t he L a rge E le c t ron Posit ron col l ider (LEP) to ok a sc a lp el to t he Ds u b a t o m ic w orl d. It s fo u r e x p e r i m e nt s – A L E PH, DE L- PHI, L3 and OPAL – turned high-energy particle physics i nt o a pr e c i s io n s c ie n c e, fi r m l y e s t a bl i s h i n g t h e e x i s t e n c eof e l e c t r o w e a k r a d i a t i v e c or r e c t io n s. L E P’s pr o g r a m m e d e t e r- m i n e d t h e nu m b e r o f n e ut r i n o f a m i l ie s t o b e t h r e e, o b s e r v e d Matthew the running of the QCD coupling constant and severely con- Chalmers strained key Standard Model parameters, to name a few Editor highlights (see p32). The machine broke new ground in the s c a l e o f pr oj e c t s i n h i g h- e n e r g y p h y s i c s, a n d e nj o y s a pr o u d place in the memories of those who worked on it (p39). One of LEP’s most important legacies, however, is the 26.7 km- c i r c u m fe r e n c e t u n n e l t h a t it b e q u e a t h e d t o t h e L HC. W it h o ut it, the rich seam of physics that is the exploration of the Higgs sector might st ill be buried. Today at CERN, 30 years after LEP’s first results, heavy m a c h i n e r y i s o n c e a g a i n c a r v i n g o ut r o c k i n t h e n a m e o f f u n- Heroic The LEP tunneling crew in January 1987 having completed damental research. Since June 2018, major civil engineering the arc from point 2 to point 3 with only 1 cm of difference. works have been taking place at points 1 and 5 (ATLAS and CMS) of the LHC to make way for the high-luminosity LHC. pinned a highly successful research programme spanning Each site requires a new shaft of 80 m deep, a service hall to a l most 50 yea rs (a nd p erhaps e ven longer), t he FCC’s lepton- house cryogenic and other equipment, a 300 m-long tunnel and subsequent hadron-collider modes would serve particle for electrical equipment and four 50 m service tunnels that physicists to at least the end of the 21st centur y. Sensing the will connect the new structures to the accelerator tunnel. By opportunity, China is drawing up plans for a similar pro- t h e t i m e t h e u n d e r g r o u n d s t r u c t u r e s a r e c o m pl e t e d i n 202 1, a gramme, benefitting from lower construction costs compared tot a l of a rou nd 100,000 m 3 of ea r t h w i l l h ave b e e n e xc av ate d. to Europe, but requiring associated infrastructure to be built Particle physics doesn’t need to dig new tunnels very often. from scratch. As for the machines that might one day occupy P r o p o s a l s for a 100 k m c i r c u l a r c ol l i d e r t o fol l o w t h e L HC h a v e these fantastic tunnels, researchers in the US have recently One of therefore attracted the interest of civil engineers and even demonstrated a record field for an advanced niobium-tin LEP’s most te c h ent repreneurs a round t he world. The ge olog ic a l, env i- accelerator dipole magnet (p7). important r o n m e nt a l a n d c i v i l e n g i n e e r i n g s t u d i e s u n d e r t a k e n d u r i n g Elsewhere in this issue, we explore tensions in the Hubble t h e p a s t fi v e y e a r s a s p a r t o f C E R N’s F ut u r e C i r c u l a r C ollider constant, report on EPS-HEP and other conferences (p19), legacies is study (FCC), in addition to similar studies for a possible Com- describe the ProtonMail success story (p53), look at ways to its 26.7 km- p a c t L i n e a r C ol l i d e r u p t o 50 k m l o n g, d e m o n s t r a t e t h e s t a t e strengthen theoretical physics in southeastern Europe (p45), circumference of the art in tunnel design and construction methods (p26). a nd more. Fi n a l ly, don’t forge t to brow s e t he ne w cerncourier. VACUUM SOLUTIONS tunnel We r e t h e FC C t o g o a h e a d, t h e n j u s t a s t h e L E P t u n n e l u n d e r- com, where ar t icles w ill be published on an ongoing basis.

Reporting on international high-energy physics

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19.08.15_ID875_CernCourier_Sept-Okt_3Prod_CombiLine_HiPace80_HiCube_Classic_213x282mm_EN_CH.indd 1 15.08.19 16:53 CCSepOct19_Editorial_v5.indd 5 29/08/2019 11:34 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM NEWS ANALYSIS if there is no second chance: AccelerAtors Advanced dipole sets high-field record sensitivity & speed Researchers in the US have demon- Fermilab The development of high-field super- strated an advanced accelerator dipole conducting accelerator magnets has magnet with a field of 14.1 T – the high- received a strong boost from high-en- est ever achieved for such a device at an ergy physics in the past decades. The @ highest precision operational temperature of 4.5 K. The current state of the art is the LHC dipole milestone is the work of the US Magnet mag nets, which operate at 1.9 K to pro- Development Program (MDP), which duce a field of around 8 T, enabling pro- PCO - the most versatile sCMOS includes Fermilab, Lawrence Berkeley ton-proton collisions at an energy of 13 Na t i o n a l L a b or a t or y (L BN L), t h e Na t i o n a l TeV. E x pl or i n g h i g h e r e n e r g i e s, u p t o 100 camera portfolio on the market High-Field Magnetic Field Laboratory TeV a t a p o s s i bl e f ut u r e c i r c u l a r c ol l i d e r, and Brookhaven National Laboratory. requires higher magnetic fields to steer The MDP’s “cos-theta 1” (MDPCT1) the more energetic beams. The goal is to

dipole, made from Nb3Sn superconduc- d o u bl e t h e fie l d s t r e n g t h c o m p a r e d t o the tor, beats the previous record of 13.8 T at LHC dipole magnets, reaching up to 16 T, 4.5 K achieved by LBNL magnet “HD2” which calls for innovative magnet design that has stood for more than 10 years, and a different superconductor compared and follows the 14.6 T at 1.9 K (13.9 T at t o t h e N b-T i u s e d i n t h e L HC. C u r r e nt l y,

4.5 K) reached by “FRESCA 2” at CERN Nb3S n (n i o biu m t i n) i s b e i n g e x pl or e d a s in 2018, which was built as a supercon- a viable candidate for reaching this goal. ducting-cable test station, rather than an High-temperature superconductors, such

accelerator magnet. Together with other a s R E B C O, M g B 2 a n d i r o n-b a s e d m a t e r i- recent advances in accelerator magnets als, are also being studied. i n E u r o p e a n d e l s e w h e r e, t h e r e s u l t s e n d s a positive signal for the feasibility of HL-LHC first

next-generation hadron colliders. The first accelerator magnets to use Nb3Sn The MDP was established in 2016 by technology are the 11 T dipole magnets t h e US D e p a r t m e nt o f E n e r g y t o d e v e l o p and the final-focusing magnets under m a g n e t s t h at o p e r at e a s c lo s e l y a s p o s- development for the high luminosity s i bl e t o t h e f u n d a m e nt a l l i m it s o f s u p e r- LHC (HL-LHC), which will be installed c o n d u c t i n g m a t e r i a l s w h i l e m i n i m i s i n g a r o u n d t h e i nt e r a c t i o n p oi nt s. B ut t h e FC C t he need for mag net training. The pro- would require more than 5000 supercon- gramme aims to integrate domestic ducting dipoles grouped for powering in pco.dicam C1 accelerator-magnet R&D and position series and operating continuously over the US in the technology development long time periods. A number of criti- pco.edge 5.5 • intensified sCMOS technology for future high-energy proton-proton cal aspects underlie the design, cost- colliders, including a possible 100 km- effective manufacturing and relia- • 100 fps @ 2556 x 2160 pixel pco.edge 4.2 bi • high resolution 2048 x 2048 pixel circumference facility at CERN under ble operation of 16 T dipole magnets in and 16 bit digitization • minimum exposure time 4 ns study by the Future Circular Collider future colliders. Among the targets for up to 95% quantum efficiency (FCC) collaboration. In addition to the Nb Sn conductor is a critical cur- • 30 000 : 1 intra scene dynamic • with 25 mm image intensifier 3 the baseline design of MDPCT1, other rent density of 1500 A/mm2 at 16 T and rolling / global / global reset back • illuminated • double image mode with design options for such a machine have 4.2 K – almost a 50% increase com- shutter modes bi 300 ns interframing time been studied and will be tested in the pared to the current state of the art. In • compact design • 10G FOL data interface coming years. Magnetic addition to the conductor, developing • multi channel option The result sends a • uv version available “T h e g o a l for t h i s fi r s t m a g n e t t e s t w as moment a n i n d u s t r y-a d a p t e d d e s i g n for 16 T d i p ol e s pco.sdk with 13.8 million fps • to limit the coil mechanical pre-load to Installation of the and other accelerator magnets with higher for Windows and Linux positive signal for • deep cooled to -25 °C • 10G FOL data interface a safe level, sufficient to produce a 14 T MDP “cos-theta 1” p e r for m a n c e pr e s e nt s a m aj or c h a l l e n g e. field in the magnet aperture,” explains dipole magnet into the feasibility of The FCC collaboration has launched • pco.sdk • pco.sdk for Windows and Linux for Windows and Linux M DP C T 1 pr oj e c t l e a d e r A l e x a n d e r Z l o bi n a test cryostat at a rigorous R&D programme towards o f Fe r m i l a b. “T h i s g o a l w a s a c h i e v e d a f t e r Fermilab. next-generation 16 T magnets. Key components are the a s h or t m a g n e t t r a i n i n g a t 1.9 K : i n t h e l a s t global Nb Sn conductor development hadron colliders 3 quench at 4.5 K t h e m a g n e t r e a c h e d 1 4.1 T. programme, featuring a network of Following this successful test the magnet a c a d e m i c i n s t it ut e s a n d i n d u s t r i a l p a r t- pre-stress will be increased to reach its ne r s, a nd t he 16 T magnet-design work s pco.de desig n limit of 15 T.” p a c k a g e s up p or t e d b y t h e EU-f u n d e d

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EuroCirCol project. This is now being The FCC 15 enabled a design and cost model for the award followed by a 16 T short-model pro- conductor magnets of FCC, demonstrating the fea- gramme aiming at constructing model 14 sibility of Nb Sn technology. development 3 Supergravity attracts Special Breakthrough Prize magnets with several partners world- 13 1.9K 4.5K “The enthusiasm of the worldwide wide such as the US MDP. Unit lengths targets superconductor community and the are very 12 S Bennett/CERN of Nb3Sn wires with performance at least achievements are impressive,” says On 6 August, theorists Sergio Ferrara of bore field (T) comparable to that of the HL-LHC con- challenging 11 Amalia Ballarino, leader of the conduc- C E R N, D a n F r e e d m a n o f M I T a n d St a n ford ductor have already been produced by tor activity at CERN. “The FCC conductor Un i v e r s it y, a n d P e t e r v a n Ni e u w e n hu i z e n industry and cabled at CERN, while, at 10 development targets are very challeng- o f St o n y Br o o k Un i v e r s it y w e r e a w a rd e d Fe r m i l a b, m u l t i-fi l a m e nt a r y w i r e pr o - 0481216 20 ing. The demonstration of a 14 T field a $3 m i l l i o n S p e c i a l Br e a k t h r o u g h P r i z e quench number duced with an internal oxidation process in a dipole accelerator magnet and the in Fundamental Physics for their 1976 has already exceeded the critical current Fig 1. Training quench history for the possibility of reaching the target critical invention of supergravity. density target for the FCC – just two MDPCT1 demonstrator magnet at Fermilab, current density in R&D wires are mile- Supergravity marries general relativity

examples of many recent advances in showing the 14.1 T field attained at 4.5 K. stones in the history of Nb3Sn conductor with supersymmetry – an important step this area.EuroCirCol, which officially and a reassuring achievement for the FCC in the quest for a unified theory of gravity wound up this year (see p23), has also magnet development programme.” and the strong and electroweak interac- tions. At the time, it was not obvious how Theory this could be done. During a short period lasting from autumn 1975 to spring the A new centre for astroparticle theory following year, Ferrara, Freedman and van Nieuwenhuizen succeeded, with the help of state-of-the-art computers, in CERN-PHOTO-201907-190-1 On 10 July, CERN and the Astroparticle producing a supersymmetric theory that Physics European Consortium (APPEC) included the gravitino as the supersym- founded a new research centre for ast- metric partner of the graviton. The trio roparticle physics theory called EuCAPT. published their paper in June 1976. Led by an international steering com- Chair of the prize selection com- mittee comprising 12 theorists from mittee, Edward Witten of the Institute institutes in France, Portugal, Spain, for Advanced Study in Princeton, says Sweden, Germany, the Netherlands, of the achievement: “The discovery Italy, Switzerland and the UK, and from of supergravity was the beginning of CERN, EuCAPT aims to coordinate and including quantum variables in describ- promote theoretical physics in the fields ing the dynamics of space–time. It is of astroparticle physics and cosmology quite striking that Einstein’s equations in Europe. admit the generalisation that we know Astroparticle physics is undergoing as supergravity.” string unification by Witten in 1995. It Super trio the LIGO and Virgo collaborations for the a phase of profound transformation, Despite numerous searches at ever played a role in Andrew Strominger and Peter van detection of gravitational waves; and explains inaugural EuCAPT director higher energies during the past decades, Cumrun Vafa’s 1996 derivation of the Nieuwenhuizen, Jocelyn Bell Burnell for the discovery of Gianfranco Bertone, who is spokes– no supersymmetric particles have been Bekenstein–Hawking entropy for quan- Sergio Ferrara and pulsars. The new laureates, a long w it h person of the Centre for Gravitation and observed. But supergravity has still had tum black holes, and is also important in Dan Freedman (left t he w inners of t he Breakt hrough Pri ze Astroparticle Physics at the University of an enormous influence on theoretical t h e h ol o g r a p h i c A d S/C F T d u a l it y d i s c o v- to right) at CERN in in Life Sciences and in Mathematics, Amsterdam. “We have recently obtained physics – especially on string theory, of ered by Juan Maldacena in 1997. 2016 on the will receive their awards at a ceremony extraordinary results such as the dis- which supergravity is a low-energy man- A Special Breakthrough Prize can be occasion of on 3 November. covery of high-energy cosmic neutri- ifestation (CERN Courier January/Febru- awarded at any time in recognition of an supergravity’s 40th “This award comes as a complete nos with IceCube, the direct detection ary 2017 p41). Supergravity was a crucial extraordinary scientific achievement. anniversary. surprise,” says Ferrara. “Supergravity of gravitational waves with LIGO and ingredient in the 1984 proof by Michael Previous winners of the physics prize i s a n a m a z i n g t h i n g b e c au s e it e x t e nd s Virgo, and we have witnessed the birth G r e e n a n d Jo h n S c h w a r z t h a t s t r i n g t h e- are: the late Stephen Hawking; seven general relativity to a higher symmetry of multi-messenger astrophysics. Yet ory is mathematically consistent, and it physicists whose leadership led to the – the dream of Einstein – but none of us we have formidable challenges ahead Merging minds Gian Giudice (head of CERN-TH), Teresa Montaruli (APPEC chair), Eckhard Elsen (CERN was also instrumental in the M-theory discovery of the Higgs boson at CERN; expected this.” of us: understanding the nature of dark director for research and computing) and Job de Kleuver (APPEC secretary-general) with the new agreement. matter and dark energy, elucidating the Facilities Project/JPL/NASA Galileo several high-priority projects, includ- origin of cosmic rays, understanding interested scientists will feel welcome These are doing at CERN-TH is an exploration of ing: high-energy electron tests; high- the matter-antimatter asymmetry to join this new initiative.” On a prac- highly inter- the possible links between physics at the CERN and ESA join forces penetration heavy-ion tests; assess- problem, and so on. These are highly tical level, EuCAPT aims to coordinate disciplinary smallest and largest scales. Creating a ment of commercial components interdisciplinary problems that have scientific and training activities, help collaborative network among European in harsh environments and modules; radiation-hard and ramifications in cosmology, particle, researchers attract adequate resources problems research centres in astroparticle phys- radiation-tolerant components and and astroparticle physics, and that are for their projects, and promote a stim- ics and cosmology will boost activities Strengthening connections between Europa modules; radiation detectors, monitors best addressed by a strong and diverse ulating and open environment in which in these fields and foster dialogue with particle physics and related disciplines, A recent project at and dosimeters; and simulation tools for community of scientists.” young scientists can thrive. CERN will particle physics,” he says. “Dark mat- CERN signed a collaboration agreement CERN evaluated the radiation effects. Important prelimi- The construction of experimental act as the central hub of the consortium ter, dark energy, inflation and the origin with the European Space Agency (ESA) on effects of radiation nary results have already been achieved astroparticle facilities is coordinated for t he first five years. of large-scale structures are big ques- 11 July to address the challenges of oper- on electronics for in some areas, including high-energy by APPEC, but until now there was no It is not a coincidence that CERN has tions regarding the universe. But there ating equipment in harsh radiation envi- the Jupiter Icy electron tests of electronics for the Europe-wide coordination of theoretical been chosen as the central hub of EuCAPT, are good hints that suggest that their ronments. Such environments are found Moons Explorer Jupiter Icy Moons Explorer (JUICE) activities, says Bertone. “We want to be says Gian Giudice, head of CERN’s theory explanation has to be looked for in the in both particle-physics facilities and (JUICE) mission. mission performed at CERN’s CLEAR/ open and inclusive, and we hope that all department. “The research that we are domain of particle physics.” outer space, and the agreement identifies VESPER facility.

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Medical physics Computing R Kaltschmidt/LBNL MedAustron debuts carbon-ion therapy MedAustron MedAustron, an advanced hadron- therapy centre in Austria, has treated its first patient with carbon ions. The medical milestone, which took place on 2 July, elevates the particle-physics-linked facility to the ranks of only six centres worldwide that can combat tumours with both protons and carbon ions. When protons and carbon ions strike biological material, they deposit a large dose in a small and well-targeted vol- ume, reducing damage to healthy tis- sue surrounding a tumour and thereby reducing the risk of side effects. While proton therapy has been successfully Heavy treatment three ion sources are pre-accelerated by a the construction of the accelerator facil- used at MedAustron since December 2016, The MedAustron linear accelerator), a synchrotron, a high- ity, is an excellent example of large-scale Paradigm shift Researchers on the NOvA and CMS experiments have already used HEPCloud to run jobs on the US National Energy Research Scientific treating more than 400 cancer patients proton/carbon-ion energy beam transport system to deliver technology transfer from fundamental Computing Center at Berkeley. so far, carbon-ion therapy opens up new synchrotron, which the beam to various beam ports, and a research to societal applications.” opportunities to target tumours that were was constructed in medical front-end, which controls the Particle therapy with carbon ions was previously difficult or impossible to treat. collaboration with irradiation process and covers all safety first used in a dedicated medical facilit y Carbon ions are biolog ically more effec- CERN and others. aspects. Certified as a medical product, in Japan in 1994, and a total of almost Cloud ser v ices ta ke off in t he US and Europe tive than protons and therefore allow a the accelerator provides proton and car- 30,000 patients worldwide have since higher biological dose to be administered bon ion beams with a penetration depth been treated with this method. Initially, Fermilab has announced the launch of was able to execute around 2 million procurement framework is being devel- to the tumour. of about up to 37 cm in water-equivalent treatment with carbon ions at MedAustron HEPCloud, a step towards a new comput- hardware threads at a supercomputer at oped in the context of the new OCRE MedAustron’s accelerator complex is tissue, and is able to deliver carbon-ions will focus on tumours in the head and ing paradigm in particle physics to deal the National Energy Research Scientific [Open Clouds for Research Environ- based on the CERN-led Proton Ion Med- w it h 255 d i ffe r e nt e n e r g ie s r a n g i n g f rom neck region, and at the base of the skull. with the vast quantities of data pour- Computing Center of the US Department ments] project.” ical Machine Study, the design subse- 120 to 400 MeV with maximum intensities But the spectrum will be continuously ing in from existing and future facili- of Energy’s Office of Science. HEPCloud The European Open Science Cloud, an quently developed by CERN, the TERA of up to 109 ions per extracted beam pulse. expanded to include other tumour types. ties. The aim is to allow researchers to project members now plan to enable EU-funded initiative started in 2015, aims Foundation, INFN in Italy and the CNAO “The first successful carbon-ion “Irradiation with carbon ions makes “rent” high-performance computing experiments to use the state-of-the- t o br i n g e ffic i e n c i e s a n d m a k e E u r o pean Foundation (CERN Courier January/Febru- treatment unveils MedAustron’s full it possible to maintain both the physi- centres and commercial clouds at times art supercomputing facilities run by research data more sharable and reusable. ary 2018 p25). Substantial help was also potential for cancer treatment,” says cal functions and the quality of life of of peak demand, thus reducing the costs t he DOE’s Adv a nced Sc ient i fic Comput- To help European research infrastruc- provided by the Paul Scherrer Institute, Michael Benedikt of CERN, who coor- patients, even with very complicated of providing computing capacity. Similar ing Research programme at Argonne and tures move towards to this open-science in particular for the gantry and beam- dinated CERN’s contributions to the tumours,” says Piero Fossati, scientific projects are also gaining pace in Europe. Oak Ridge national laboratories. future, a €16 million EU project called delivery designs. The MedAustron system project. “The realisation of MedAustron, and clinical director of MedAustron’s “Traditionally, we would buy enough ESCAPE (European Science Cluster of comprises an injector (where ions from through the collaboration with CERN for carbon-ion programme. computers for peak capacity and put Europe’s Helix Nebula Astronomy & Particle Physics ESFRI) was them in our local data centre to cover CERN is leading a similar project in launched in February. The 3.5 year-long our needs,” says Fermilab’s Panagiotis Europe called the Helix Nebula Science project led by the CNRS will see 31 facil- a lternative gr avity field values, while dark-blue regions Spentzouris, one of HEPCloud’s drivers. Cloud (HNSciCloud). Launched in 2016 ities in astronomy and particle physics correspond to to a very small scalar “However, the needs of experiments are and supported by the European Union collaborate on cloud computing and data Galaxies thrive fields, i.e. regions where screening not steady. They have peaks and valleys, (EU), it builds on work initiated by EIRO- science, including CERN, the European is active and the theory behaves like so you want an elastic facility.” All Fer- forum in 2010 and aims to bridge cloud Southern Observatory, the Cherenkov on new physics general relativity. The right-half of the milab experiments will soon submit jobs computing and open science. Working Telescope Array, KM3NeT and the Square image shows the gas density with stars to HEPCloud, which provides a uniform with IT contractors, HNSciCloud mem- Kilometre Array (SKA). This supercomputer-generated image over-plotted. The simulation, which interface so that researchers don’t need bers have so far developed three proto- In the context of ESCAPE, CERN is of a galaxy suggests that general was based on a total of 12 simulations expert knowledge about where and how type platforms and made them accessible leading the effort of prototyping and relativity might not be the only way to for different model parameters and best to run their jobs. to experts for testing. implementing a FAIR (Findable, Acces- explain how gravity works. Theorists at resolutions and required a total runtime The idea dates back to 2014, when “The HNSciCloud pre-commercial sible, Interoperable, Reproducible) data Durham University in the UK simulated of about 2.5 million core-hours, shows Spentzouris and Fermilab colleague procurement finished in December infrastructure based on open-source the universe using hydrodynamical that spiral galaxies like our Milky Way Lothar Bauerdick assessed the volumes 2018 having shown the integration of software, explains Simone Campana simulations based on “f(R) gravity” could still form even with different laws of data coming from Fermilab’s neutrino commercial cloud services from sev- of CERN, who is deputy project leader – in which a scalar field enhances of gravity. “Our research definitely programme and the US participation in eral providers (including Exoscale of the Worldwide LHC Computing Grid gravitational forces in low-density does not mean that general relativity CERN’s Large Hadron Collider (LHC) and T-Systems) with CERN’s in-house (WLCG). “This work complements the regions (such as the outer parts of a is wrong, but it does show that it does experiments. The first demonstration capacity in order to serve the needs of The aim WLCG R&D activity in the area of data galaxy) but is screened by the so-called not have to be the only way to explain of HEPCloud on a significant scale was the LHC experiments as well as use cases is to allow organisation, management and access chameleon mechanism in high-density gravity’s role in the evolution of the in February 2016, when the CMS exper- from life sciences, astronomy, proton researchers in preparation for the HL-LHC. In fact, environments such as our solar system. universe,” says lead author Christian iment used it to achieve about 60,000 and neutron science,” explains project to rent high- the computing activities of the CERN The left-half of the image shows the Arnold of Durham University’s Institute cores on the Amazon cloud, AWS, and, leader Bob Jones of CERN. “The results experiments at HL-LHC and other initi- scalar field of the theory: bright yellow for Computational Cosmology. (Nature later that year, to run 160,000 cores using and lessons learned are contributing performance atives such as SKA will be very similar in regions correspond to large scalar- Astronomy; arXiv:1907.02977.) Google Cloud Services. Most recently in to the implementation of the European computing scale, and will likely coexist on a shared May 2018, the NOvA team at Fermilab Open Science Cloud where a common centres infrastructure.”

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we will certainly look.” in Japan: neutrons are expected London College Imperial 18F, 99mTc, 11C, 13N, 15O, to excite the gadolinium nuclei, Best 15 15 64Cu, 67Ga, 124I, 103Pd M87* has more angular momentum IceCube gets first major upgrade which should then emit observ- than any other measured object. Seven strings of optical mod- able photons after a short delay. Best 15 + 123I, Best 20u/25 20, 25–15 ules will be added to the bottom- This technique will also be used at 111In, 68Ge/68Ga Black-hole image constrains centre region of the IceCube neu- Super-Kamiokande, to help distin- Best 30u Best 15 + 123I, ultra-light dark matter trino observatory at the South guish neutrinos and antineutrinos Brookhaven’s Hooman Davoudiasl Pole, after US, Japanese and Ger- in CP-violation studies. 30 111 68 68 (Upgradeable) In, Ge/ Ga and Peter Denton have used the man institutions fully funded the Greater production of recent Event Horizon Telescope detector’s first major upgrade. The THz accelerators build up STEAM Best 35 35–15 Best 15, 20u/25 isotopes image of supermassive black hole new strings will be placed within a DESY physicists have taken a critical M87* to disfavour “fuzzy” mod- highly instrumented central region step forward in demonstrating the Cold atom interferometry was used to 201 81 81 plus Tl, Rb/ Kr els of ultra-light boson dark mat- of IceCube called DeepCore, but feasibility of miniature accelerators place limits on dark energy models. 82Sr/82Rb, 123I, 67Cu, ter (DM) with masses of the order with even more closely spaced and powered by terahertz radiation, by Best 70 70–35 Installation of Best 70 MeV -21 81Kr + research of a few 10 eV (Phys. Rev. Lett. 123 tightly packed sensors, reducing delivering a record 70 keV at a peak Table-top experiment Cyclotron at INFN, Legnaro, Italy 021102). The inferred mass, spin and IceCube’s neutrino-energy thresh- accelerating gradient of 200 MV/m constrains dark energy age of the black hole are incom- old to a few GeV. The primary goals (Optica 6 872). The feat - the first Physicists at Imperial College Lon- patible with the existence of such are to measure neutrino oscillations time a THz accelerator has doubled don and The University of Notting- fuzzy DM given the principle of to tau neutrinos and reduce system- the energy of a beam - was accom- ham have placed stringent limits superradiance, whereby quantum atics relating to optical scattering plished using two Segmented THz on the “chameleon” and “symmet- fluctuations deplete the angular and absorption in the ice. Research- Electron Accelerator and Manip- ron” theories of modified gravity momentum of a rotating black hole ers also hope to shed light on the ulator (STEAM) devices. The first (Phys. Rev. Lett. 123 061102). Given The BG-75 Biomarker Generator is a revolutionary 400 MeV Rapid Cycling Medical Synchrotron by populating a cloud of bosons neutrino mass hierarchy and sterile shortens the electron bunches from the empirical success of the weak- development in radio-pharmaceutical production for Proton-to-Carbon Heavy Ion Therapy: around it. The effect depends only neutrinos. The 700 or so new opti- 0.3 to 0.1 mm so that they may be field limit of general relativity, that delivers a single or batch dose of 18F-FDG, and on the bosons’ mass, and does not cal modules are two to three times coherently accelerated in the second. these dark-energy models propose 18 Intrinsically small beams facilitating presuppose any non-gravitational more sensitive than the 5160 sen- THz-driven electron acceleration screening mechanisms whereby the additional advanced F biomarkers on demand. beam delivery with precision interactions. Future measurements sors already embedded in the ice, has recently emerged as a promis- new forces are weaker when there is The system provides integration of all components of M87* and other spinning super- and will pave the way for IceCube- ing approach for developing compact more matter around - the opposite needed to produce and qualify PET biomarkers Small beam sizes – small magnets, massive BHs have the potential to Gen2 - a planned extension with X-ray sources for materials science of how gravity behaves. The UK team light gantries – smaller footprint exclude the entire parameter space 10 times greater volume. and medical imaging. 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Nν = 2.9840 ± 0.0082, obtained 30 (protons and/or carbon), beam years ago (see p32), will be revised Largest CCD array complete Beauty baryons discovered delivery modalities even closer to three thanks to new Brookhaven National Laboratory has The LHCb Collaboration has dis- calculations of LEP’s integrated m a r k e d t h e e n d o f a 16-y e a r pr oj e c t covered two new resonances in luminosity. Inspired by design to construct the world’s biggest the combined Run 1 and Run 2 + - 0 + - studies for future e e colliders, Carrie McGivern of Fermilab inspects charge-coupled-device array. The Λbπ π invariant mass spectrum. 0 Georgios Voutsinas of CERN and co- ANNIE phototubes. 3.2 gigapixel sensor will be used in The new states, dubbed Λb(6146) 0 0 workers have improved the cal- the camera of the Large Synoptic and Λb(6152) , join Λb(5912) and 0 culation of the beam-beam effect, ANNIE prepares for action Survey Telescope (LSST), which is Λb(5920) , which were discovered ion Rapid Cycling Medical whereby electromagnetic forces The Accelerator-Neutrino-Neutron currently under construction in by the collaboration in 2012. The between dense bunches of electrons Interaction Experiment (ANNIE) is Chile. Also boasting a mirror the masses are consistent with the- Synchrotron (iRCMS) 0 and positrons degrade the beam now installed and being commis- width of a tennis court, the detector oretical predictions for Λb(1D) quality. They conclude that LEP’s sioned at Fermilab, in preparation will record 15 TB of data per night, states with JP = 3/2+ and 5/2+, but true integrated luminosity is about for beam this autumn. ANNIE with each image capturing a solid their interpretation as other excited 0 0.1% higher than previously thought will measure neutron yields from angle equivalent to 40 full moons. beauty baryons, such as neutral Σb TeamBest Companies © 2019 * Best iRCMS is under development and not available for sale currently. (arXiv:1908.01704). The only preci- neutrino-nucleus interactions in LSST’s goals encompass map- states, cannot be excluded. The s io n e l e c t r o w e a k o b s e r v a bl e a ffe c t e d water. As well as testing the per- ping galaxies for the study of dark ongoing studies provide detailed www.bestcyclotron.com • www.bestabt.com • www.bestproton.com is expected to be the peak Z cross formance of newly commercialised energy and dark matter, providing a tests of the quark model. 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Reports from the Large Hadron Collider experiments ULTRA AVAILABLE CMS AMPLIFIERS CMS revisits rare and beautiful decays The Bs meson is a bound state of a strange quark and a beauty antiquark – as such it possesses both beauty and strange- FOR ACCELERATOR & ness. For many years the search for its extremely rare decay to a μ+μ– pair was a holy grail of particle physics, because MEDICAL APPLICATIONS of its sensitivity to theories that extend the Standard Model (SM). The SM pre- + – dicts the decay rate for Bs → μ μ to be only about 3.6 parts per billion (ppb). TMD in collaboration with Rosatom - NIITFA is now able to Its lighter cousin, the B0, which is made offer revolutionary, ultra-available RF solid state amplifiers from a down quark and a beauty anti- quark, has an even lower predicted for scientific and medical applications. branching fraction for decays to a μ+μ– pair of 0.1 ppb. If beyond-the-SM parti- Innovative power combining and control system results in: cles exist, however, the predictions could be modified by their presence, giving the decays sensitivity to new physics • Ultra-compact systems, typically one Applications: that rivals and might even exceed that of direct searches. 19” rack / 100 kW (pulse) • Synchrotrons, LINACs for scientific, It took more than a quarter of a cen- Beauty and strangeness Two muons (red) emerge from a Bs → μμ decay candidate in the CMS Run 2 data. • CW / Pulse Systems, long pulse experimentation/particle physics tury of extensive effort to establish The inset shows the displacement of the decay vertex from the collision point (yellow). B → μ+μ–, a nd t he fi rst obser v at ion w a s • Modular Solid State architecture, and Spallation systems s presented in 2013, in a joint publication was set on its rate. compact modules (<10 kg) –1 –1 –1 • Medical therapy equipment by the CMS and LHCb collaborations ×10–9 36 fb (13 TeV) + 20 fb (8 TeV) + 5 fb (7 TeV) CMS also managed to measure the 0.8 based on LHC Run 1 data. The same e ffe c t i v e l i fe t i m e o f t h eB meson using Courtesy Honeywell Aerospace • Highly Maintainable with Hot Swap • Cyclotrons for radioisotope CMS s paper reported evidence for B0 + – the several dozen B + – decay events capability production → μ μ preliminary s →μ μ with a significance of three standard 0.7 that were observed. The interest in • Wall Plug efficiency competitive with • Option to upgrade existing systems deviations, however, this signal has not measuring this lifetime is that, just tube technology (55% demonstrated) subsequently been confirmed by CMS, as for the branching fraction, new • Highly robust to VSWR mismatch Other Products: LHCb or ATLAS analyses. A new CMS 0.6 physics might alter its value from the Run 2 analysis now looks set to bolster SM expectation. This measurement • High MTBF and Low MTTR • High Power, Very Low Phase Noise interest in these intriguing decays. yielded a lifetime of about 1.7 ps, con- 0.5 TWT Amplifiers The CMS collaboration has updated ) sistent with the SM. The measured CMS • No loss of power from any single – μ element failure • Brazed UHV components its 2013 analysis with higher centre-of- + value is also consistent with the only mass-energy Run 2 data from 2016, per- 0.4 other such lifetime measurement, per- + – → μ • High efficiency enhances reliability • Electron Guns mitting an observation of Bs → μ μ with 0 formed by LHCb. a s i g n i fic a n c e o f 5.6 s t a n d a r d d e v i a t i ons With three times more Run 2 data yet

• Frequencies available from BF(B (fi g u r e 1). T h e r e s u lt s a r e c o n s i s t e nt w ith 0.3 to be analysed by CMS, the next update 20 MHz to 1.3 GHz the latest results from ATLAS and LHCb, – based on the full Run 1 and Run 2 and while no significant deviation from datasets – may shed more light on this • MW power capability 0.2 the SM is observed by any of the experi- fascinating corner of physics, and move ments, all three decay rates are found to SM us closer to the ultimate goal, which is 0 + – lie slightly below the SM prediction. The 0.1 the observation of the B → μ μ decays. For more information on our leading edge sl ig ht defic it i s not sig n i fic a nt, but t he trend is intriguing because it could be Further reading technology email us at [email protected] related to so-called flavour anomalies 0 CMS Collaboration 2019 CMS-PAS- recently observed by the LHCb experi- 024 6 8 BPH-16-004. or visit www.tmd.co.uk 0 + – ×10–9 ment in other rare decays of B mesons BF(Bs → μ μ ) CMS and LHCb collaborations 2015 Nature (CERN Courier May/June p9). This makes 522 68. the new CMS measurement even more Fig. 1. Probability contours representing the simultaneous LHCb Collaboration 2017 Phys. Rev. Lett.

exciting. The new analysis showed no measurement of the relative probabilities for Bs → μμ and 118 191801. sign of B0 → μ+μ–, and a stringent 95% B0 → μμ decays. The contours correspond to one to five standard ATLAS Collaboration 2019 J. High Energy confidence limit of less than 0.36 ppb deviations, and the red point indicates the SM predictions. Phys. 04 098.

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ALICE momentum of the Higgs boson and the c r o s s s e c t i o n (fi g u r e 2) h a s s i g n i fic a nt ly number of jets produced in association ATLAS preliminary improved in precision compared to ear- –1 w it h it. T h e d i ffe r e nt pr o d u c t i o n m ech- 1.6 √s = 13 TeV, 139 fb lier results. It is sensitive to the vir- Bottomonium elliptic-flow no-show anisms of the Higgs boson are measured tual processes governing the dominant inclusively and in various regions of kin- combined data Higgs-boson production through gluon 1.2 High-energy heavy-ion collisions at the small number of available bottom quarks. ematic phase space, which are cleanly H → γγ fusion and to direct contributions from H → ZZ* → 4I [pb/GeV] LHC give rise to a deconfined system of ALICE Pb–Pb √s = 5.02 TeV 5–60% The ALICE collaboration recently separated by neural networks. new physics. NN T,H NNLOPS K = 1.1, + XH quarks and gluons called the quark–gluon 0.20 2.5 < y < 4 reported the first measurement of the In the high-statistics γγ channel, 0.8 Achieving 8% precision on the Higgs /dp

pl a s m a (Q GP). O n e o f it s m o s t s t r i k i n g fe a- inclusive J/ψ elliptic flow of the ϒ(1S) meson in lead– differential cross sections are meas- σ cross section is a significant step d t u r e s i s t h e e m e r g e n c e o f c ol l e c t i v e m o t i o n 0.15 ϒ(1S) lead (Pb–Pb) collisions using the full ured for a set of variables related to 0.4 towards studying the electroweak sym- due to pressure gradients that develop at ϒ(1S), TAMU model Pb–Pb data set of LHC Run 2 (figure 1). the Higgs boson kinematics, as well as metry breaking mechanism. Numerous t h e c e nt r e. D i r e c t e x p e r i m e nt a l e v i d e n c e The measured values of the (1S) v are the kinematics and multiplicity of jets additional measurements are being pur- ϒ(1S), BBJS model ϒ 2 0.0 for t h i s c ol l e c t i v e m o t i o n i s t h e o b s e r v a- 0.10 small and consistent with zero, making produced in association with the Higgs sued by ATLAS in the Higgs-boson sector 2 1.4 v t io n o f a n i s o t r o pic flo w, w h ic h t r a n s l a t es b o t t o m o n i a t h e fi r s t h a d r o n s t h a t d o not boson. The measured distributions are with the full Run 2 dataset to perform the asymmetry of the initial geometry 0.05 seem to flow in heavy-ion collisions at u s e d t o c o n s t r a i n m o d i fie d i nt e r a c t i o n s 1.0 detailed tests of SM predictions and hunt i nt o a fi n a l-s t a t e m o m e nt u m a n i s o t r o p y. the LHC. Compared to the measured ν2 o f of the Higgs boson with SM particles. for new phenomena.

It s m a g n it ud e i s q u a nt i fie d b y h a r m o n ic inclusive J/ψ in the same centrality and The measurements in both channels data/theory 0.6 coefficientsv i n a Fo u r ie r d e c o m p o s it io n 0 p intervals, the v of (1S) is lower by are found to be well described by the Further reading n T 2 ϒ 0 20 40 80 200 1000 of the azimuthal distribution of particles. 2.6 standard deviations. The results are SM predictions. Their combination ATLAS Collaboration 2019 ATLAS-CONF- pT,H [GeV] As a result of the almond-shaped geom- –0.05 also consistent with the small, positive yields a total Higgs-production cross 2019-025. etr y of t he interact ion volume, t he larg- values predicted by models that include section of 55.4 ± 4.3 pb, in agreement Fig. 2. Differential cross section for the trans verse momentum ATLAS Collaboration 2019 ATLAS-CONF- e s t c o nt r i b ut io n t o t h e a s y m m e t r y i s t h e 246 810 no or small regeneration of bottomonia with the SM prediction of 55.6 ± 2.5 pb. of the Higgs boson as measured from the H → ZZ* → 4 ℓ and 2019-029. second coefficient, or “elliptic flow”,v . by the recombination of bottom quarks The combined measurement of the H → γγ channels and their combination, compared to the ATLAS Collaboration 2019 ATLAS-CONF- 2 pT (GeV/c) A positive v2 has been measured for interact ing in t he QGP. transverse-momentum differential SM prediction (light blue). 2019-032.

a large variety of particles, from pions, Fig. 1. ϒ(1S) elliptic flow versus p T for the 5–60% centrality These observations, in combination protons and strange hadrons up to the interval. (Centrality estimates the degree of overlap between the with earlier measurements of the sup- LHCb heavier J/ψ me s on. The l at te r i s a c u r ious two colliding nuclei, with 0% corresponding to head-on collisions.) pression of ϒ(1S) and J/ψ, support the case as quarkonia such as J/ψ are bound The measurements are compared with inclusive J/ψ and predictions scenario in which charmonia dissociate Chasing charged-lepton-flavour violation s t a t e s o f a h e a v y q u a r k (c h a r m or b o t t o m) from theoretical models of non-central Pb–Pb collisions. a n d r e for m i n t h e Q GP, w h i l e b o t t o m o n i a a n d it s a nt i q u a r k (CERN Courier December a r e d o m i n a nt l y d i s s o c i a t e d a t e a rl y s t a g e s 2017 p1 1). Q u a r k o n i a c o n s t it ut e i nt e r e s t i n g Bottomonia ised charm quarks. More massive still, of the collisions. Future datasets, to be P r o c e s s e s w h e r e t h e fl a v o u r o f c h a r g ed probes of the QGP because heavy-quark a r e t he fi r st a n d h a v i n g a h i g h e r bi n d i n g e n e r g y t h a n collected during LHC runs 3 and 4 after a leptons is not conserved are undetect- LHCb 120 LHCb 3 pairs are produced early and experience hadrons that charmonium, the dissociation of botto- major upgrade of the ALICE detector, will ably rare in the Standard Model (SM). data BDT bin 4 t h e f u l l e v olut io n o f t h e c ol l i s io n. I n h e a v y- monium ϒ(1S) is expected to be limited significantly improve the quality of the For neutral leptons, flavour violation is do not seem to background only 80 ion collisions at the LHC, charmonia, such to the early stage of the collision when present measurements. known to occur in neutrino oscillations, signal model flow in heavy- 2 as the J/ψ, d i s s o c i a t e d u e t o s c r e e n i n g f r o m t he temperat ure of t he sur rounding QGP but charged-lepton-flavour violation 40 f r e e c ol o u r c h a r g e s i n t h e Q GP, a n d r e g e n- ion collisions medium is high. Its regeneration is not Further reading (CLFV) is so suppressed that, if observed, erate by the recombination of thermal- at t he LHC e x pec ted to be sig n i fica nt because of t he ALICE Collaboration 2019 arXiv:1907.03169. it would provide indisputable evidence 0 1 candididates/(0.05 MeV) of physics beyond the SM. candidates/(15 MeV) 2 ATLAS The LHCb collaboration recently 0 reported the results of searches for two –2 0 pull + K+ ± e–+ and B 0 ± –+, Run 2 data set pins dow n Higgs-boson proper t ies CLFV decays, B → μ (s)→ τ μ 4500 5000 5500 6000 4.6 4.8 5.0 5.2 5.4 5.6 5.8 using 3 fb–1 of data collected in 2011 and + – + m(K μ e ) [MeV] MB [GeV] 2012. The two decays provide comple- The LHC completed its Run 2 operations ery of the Higgs boson, and are ideal mentary information as their final states Fig. 1. Left: the invariant mass distribution of B+ → K+ μ– e+ candidates in Run 1 data, along with the fitted in December 2018, delivering a large ATLAS preliminary H → ZZ* → 4I for pre c i sion mea su re me nt s t h at c ou ld involve c ha rged leptons from different background (blue) and an illustration of the signal shape normalised to 10 events (dashed red). –1 0 ± +– dataset of proton–proton collisions at 13 TeV, 139 fb re ve a l s ub t le e ffe c t s f rom ne w p hy s ic s. families, and both represent experi- Right: the reconstructed mass distribution for Bs → τ μ candidates in the highest-purity subsample, a cent re-of-mass energ y of 13 TeV. The 120 ATLAS presented updated results for mental challenges for LHCb. While the with the fit projection for the background-only hypothesis and normalised residuals. AT L A S d e t e c t or m a i nt a i n e d a h i g h l e v e l t h e s e t w o c h a n n e l s u s i n g t h e f u l l R u n 2 detector performance is excellent for data o f r e a d i n e s s a n d p e r for m a n c e t h r o u g h- Higgs (125 GeV) d a t a s e t a t t h e 2019 s u m m e r c o n fe r e n c e s. muons, it is more difficult to reconstruct decays recorded by the detector, LHCb extensions to the SM that address them o ut R u n 2, r e s u l t i n g i n 139 fb–1 o f d a t a for ZZ* Using improved identification and electrons and taus. The difficulty with has established the most stringent upper also predict CLFV, with branching ratios tXX, VVV + + ± – 0 ± – 80 – + + physics analyses. Z+jets, tt energy calibration of leptons, photons electrons is related to energy losses via limits on the branching fractions of these for B → K μ e and B s( ) → τ μ , which are An increasingly consistent picture uncertainty a n d j e t s, a n d n e w a n a l y s i s t e c h n iq u e s, a bremsstrahlung radiation. Meanwhile, decays: 9.5 × 10–9 for B+ → K+ μ− e+, 8.8 × 10–9 within LHCb’s reach. The latest LHCb + + + – –5 0 ± –+

of the properties of the Higgs boson is events/2.5 GeV s a m pl e o f a b o ut 2 10 H → ZZ* → 4 ℓ s i g n a l the short-lived tau leptons are always for B → K μ e , 1.4 × 10 for B → τ μ , results therefore impose strong new –5 0 ± +– being draw n in light of the Run 2 data. 40 events (figure 1) and 6550 H → γγ sig- reconstructed from their decay products, and 4.2 × 10 for Bs → τ μ (all at the constraints on beyond-SM models. The While the T h i s i s t h a n k s t o a w i d e r a n g e o f m e a s- nal events were selected to perform a which include at least one neutrino, and 95% c o n fid e n c e l e v e l). T h e l a t t e r i s a lso analyses also open the door to further 0 ± –+ detector urements, and particularly through s e r i e s o f m e a s u r e m e nt s. T h e pr o p e r t i e s thus part of the tau’s energy is unavoid- t he first ever limit on B s → τ μ . LHCb tests of CLFV by demonstrating the performance the establishment of its couplings with 0 of t he Higgs boson are investigated by ably lost. In both cases, the analyses are CLFV decays of B-mesons are particu- feasibility of searches for rare processes t h i rd-gener at ion qua rk s fol low i ng t he measuring inclusive, differential and able to recover some of the lost infor- l a rl y i nt e r e s t i n g i n l i g ht o f r e c e nt fl a v o u r w it h final-state elect rons and taus. 80 100 120 140 160 is excellent for observation of the H → bb decay and per-production-mode cross sections mation and improve the resolution by anomalies, whereby LHCb found hints muons, it is m4I [GeV] + – associated ttH production. that are sensitive to different model- exploiting constraints on the kinematics that the decay rates for b → sμ μ and more difficult Further reading The H → γγ and H → ZZ* → 4ℓ final Fig. 1. Distribution of the invariant mass of the four leptons ling aspects. and topology of the decay. b → se+e– are not equal (CERN Courier May/ LHCb Collaboration LHCb-PAPER- to reconstruct s t a t e s, w h e r e 4 ℓ d e n o t e s 4 e, 2 e 2 μ or 4μ, selected in the H → ZZ* → 4ℓ final state using the full Run 2 In the 4ℓ channel, differential Ne it h e r s e a r c h fo u n d a s i g n a l (fi g u r e 1), June 2019 p33). While the anomalies are 2019-016. provide clean experimental signatures dataset. The Higgs boson corresponds to the excess of events at cross-section measurements are per- but thanks to these reconstruction tech- most suggestive of the violation of lepton electrons LHCb Collaboration LHCb-PAPER- s that played a leading role in the discov- 125 GeV (light blue) over the non-resonant ZZ* background (red). for m e d a s a f u n c t io n o f t h e t r a n s v e r s e niques and the large quantity of B-meson flavour universality, several proposed and taus 2019-022.

16 CERN COURIER SEPTEMBER/OCTOBER 2019 CERN COURIER SEPTEMBER/OCTOBER 2019 17

CCSepOct19_Energyfrontiers_v3.indd 16 29/08/2019 09:09 CCSepOct19_Energyfrontiers_v3.indd 17 29/08/2019 09:10 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM CERNCOURIER.COM DETISIN FETE FIELD NOTES eneric High Speed D Reports from events, conferences and meetings Our ready-to-prototype generic high-speed One level above the fi rmware is the lowest EuropEan physical sociEty confErEncE on high-EnErgy physics DAQ solution is based on experience with software component – the kernel module. The different diagnostic and low-level control kernel module implements DMA functionality, devices that we have integrated throughout access to device registers and interrupt the years. handling. All the functionality of the module Ghent event sur veys future of t he field is generic PCI Express communication and The digitizer part of these applications is D Perepelitsa does not include DAQ-specifi c functionality. Almost 750 high-energy physicists met (NNLO) calculations to two-to-three not in the domain or of interest to beam 3 This keeps the complexity of the module to a from 10–17 July in Ghent, Belgium, for the processes, a nd t he latest moves to N LO diagnostics or RF physicists. From a minimum. By using the same kernel module 2019 edition of EPS-HEP. The full scope calculations. physicist’s point of view, the most important in all the applications, we make sure that the of the field was put under a microscope The flavour-physics scene was updated part of the application is the analogue front code running in the kernel is well tested and by more than 500 parallel and plenary with new SM-consistent constraints end and signal processing of acquired ADC stable. talks and a vibrant poster session. The from Belle on the ratios R(D) and R(D*), data, which is specifi c to each application. ongoing update of the European Strategy somewhat lessening the suggestion These can often be specifi c to the machine The most complex part of the software stack for Par ticle Physics (ESPP) was a strong of lepton-universality violation in B- and can vary from institute to institute, is the user-space library which is written focus, and the conference began with a meson decays. With the advent of Belle which is why off-the-shelf solutions might in C. By pushing all the complexity to the C session jointly organised by the Euro- II, and the impending analysis of LHCb’s not be adequate. The system avoids library, we achieve two things: p e a n C o m m it t e e for F ut u r e A c c e l e r a t or s f u l l R u n 2 d a t a s e t, t h e fl a v o u r a n o m a l i e s “reinventing the wheel” for every device 1. The kernel module can stay the same for to seek further input from the commu- will surely soon be confirmed or resolved. based on a digitizer board, to prevent all the applications. This allows for a well- n it y a h e a d o f t h e p u bl i c a t i o n o f t h e E SPP L HC b a l s o pr e s e nt e d n e w m e a s u r e m e nt s separate development of common parts and tested code running in the kernel, where briefing book in September. of the gamma angle of the unitarity trian- to provide a generic interface for devices bugs are typically hard to fi nd and cause The accepted view, explained ESPP gle, which show a mild 2σ t e n s i o n b e t w e e n throughout the accelerator. + a n d B 0 d e c a y s. more inconveniences than in user space. s e c r e t a r y H a l i n a A br a m o w ic z, i s t h a t a n the values obtained from B s Diagnostic devices such as BPMs, BCMs and The custom algorithm development process electron–positron collider should suc- Meanwhile, long-baseline neutrino- 2. The board can be easily integrated into low-level controls, for example LLRF, can all thus becomes more hardware/software ceed the Large Hadron Collider (LHC). Making tial social outcomes, less than a third oscillation experiments provided tan- any control system framework. Since be considered to be digitizer boards with independent, allowing physicists to develop The question is whether to build a lin- connections feel adequately supported to engage in talising information on leptonic CP the main functionality is included in the some custom FPGA processing and specifi c independently of the control system group, ear collider that is extendable to higher EPS-HEP t e c h n ol o g y t r a n s fe r. D e l e g a t e s a g r e e d o n violation, with T2K data excluding CP library, the CS-specifi c applications only analogue front ends. Their underlying with tools they know well (i.e. Matlab). energies, or a circular collider whose participants the need for more recognition for those conservation at 2σ irrespective of the need to provide a link between the library functionality is the same – gather some The software/fi rmware architecture keeps infrastructure could later be reused size up the future w h o u n d e r t a k e t h i s c r u c i a l w or k . C E R N’s neutrino mass hierarchy, and NOVA disfa- and CS. signals, process them and sometimes the main processing core the same for all the for a hadron collider. DESY’s Christo- of the field. Graeme Stewart highlighted the simi- v o u r i n g a n i n v e r t e d h i e r a r c h y o f n e ut r i n o provide an output. All these applications applications. This reduces development When application-specifi c processing phe Grojean weighed up the merits of a lar plight of theorists developing event mass eigenstates at 1.9σ. thus require generic DAQ functionality, while and maintenance costs, and the number is added to the FPGA, the library can be Large Electron Positron collider (LEP)- g e n e r a t or s, w h o s e w or k i s o f t e n n o t a d e- each of them adds signal processing specifi c of different hardware that need to be kept extended to provide access to the existing style Z-pole run at a high-luminosity quately rewarded or supported. The field Background checks to the application. in stock. functionality. circular machine – a “tera-Z factory” a l s o n e e d s t o k e e p p a c e w it h c o m p ut i n g A refrain common to both collider and – against the advantages of the polar- developments outside the field, he said, non-collider searches for dark-matter The key properties of the solution are: The common core for digitizer-related The idea of a generic FPGA core for several i s e d b e a m s pr o p o s e d a t l i n e a r f a c i l it ie s, by designing data models and code that candidates was the need to eliminate • Out of the box support of generic functionality is not the only aspect of these devices is not new, but the MTCA.4 standard and questioned the value of polarisation are optimised for graphics-process- backgrounds. A succession of talks scaled digitizer functionality (fi rmware, driver, devices that can be generalized. Extra offers more fl exibility due to the concept of to measurements of the Higgs boson at ing units rather than CPUs (central- the 90 orders of magnitude in mass that library, screens). common interfaces, such as MPS, can be rear transition modules (RTMs). By using e n e r g i e s a b o v e 250 GeV. Furthermore, he processing units). dark-matter candidates might occupy. • Ability to extend the FPGA core with identifi ed and added later. RTMs, the same digitizer board can serve said, sensitivities should be evaluated in The beginning of the main EPS con- CERN’s Kfir Blum explained that: “The several applications by having a customized application-specifi c code. Architecture l i g ht o f t h e e x p e c t e d p e r for m a n c e o f t h e ference was dominated by impressive problem with gravity is that it doesn’t • Control system framework independent Starting bottom up (from hardware), we analogue front end. This also simplifi es high-luminosity LHC (HL-LHC). new results from ATLAS and CMS, as matter if you’re a neutrino or a rhinoceros library allowing easy integration into have the fi rmware that provides support for having items on stock, since the board can they begin to probe Higgs couplings to – if you sit on a geodesic you’re going to any framework. generic digitizer functionality and leaves be turned into a BPM, BCM, etc by simply Blue skies required s e c o n d-g e n e r a t i o n fe r m i o n s, a n d a s t h e m o v e i n t h e s a m e w a y,” m a k i n g it d i ffic u l t • Option for an application-specifi c enough room for custom signal processing fl ashing the correct fi rmware. Presentations on accelerator and detector experiments continue to search for new to infer the nature of dark matter with c h a l l e n g e s e m p h a s i s e d t h e i m p or t a n c e o f phenomena and rare processes. Several cosmological arguments. Nevertheless, analogue front end due to the concept applications. The custom part can be added The solution aims to minimize the time spent s h a r i n g d e v e lo p m e nt b e t w e e n c o m p e t- speakers noted that the LHC even has h e r e p or t e d w or k o n t h e r e c e nt bl a c k-h ol e of rear transition modules (RTMs) in in addition to the digitizer functionality, on integration of the board and provide ing projects: while detector technology the potential to exceed LEP in precision i m a g e f r o m t h e Ev e nt Hor i z o n Te l e s c o p e, MTCA.4 standard. keeping the basic core common for all a ready-to-prototype base system with for a n e l e c t r o n–p o s it r o n m a c h i n e c o u l d e l e c t r o w e a k p h y s i c s: a l t h o u g h t h e h a d- which excludes some models of ultra-light The system allows for immediate applications. supported generic DAQ functionality and a b e g i n pr o d u c t i o n w it h i n a b o ut fi v e y e a r s, r o n ic e n v i r o n m e nt i n c r e a s e s s y s t e m a t ic dark matter (see p13). Above this, helio- prototyping. Even if the user is not a possibility to add custom signal processing pr o p o s e d h a d r o n c ol l i d e r s r e q u i r e a t e c h- uncertainties, deviations arising from s c o p e s s u c h a s C A S T c o nt i nu e t o e n c r o a c h software engineer, the setup provides basic cores to the FPGA. nological leap in both radiation hardness beyond-Standard Model (SM) phenomena on the parameter space of QCD axions, building blocks that can be used to facilitate a n d r e a d o ut s p e e d. C E R N’s A r i e l l a C a t t a i a r e e x p e c t e d t o s c a l e w it h t h e c e nt r e- o f- while more novel haloscopes cut thin an iterative development procedure of expressed concern for excessive utili- The accepted m a s s e n e r g y s q u a r e d. G iu l i a Z a n d e r i g h i sw at hes dow n to low coupl ings in t he 20 physics-related algorithms without requiring t a r i a n i s m i n d e t e c t or d e v e l o p m e nt, w it h view is that of the Max Planck Institute and Claude order s of m a g n it ude of m a ss e x plore d b y daily services from control specialists. only 5% of R&D being blue-sky despite an electron– D u h r o f C E R N a l s o h i g h l i g ht e d t h e n e e d sea rc hes for a x ion-l i ke pa r t ic les. Mea n- If the user does not have FPGA programming Contact us: the historical success of this approach to improve the precision of theoret- while, searches for WIMPs are sensitive Author positron experience, initial prototyping can simply Cosylab., Control System Laboratory in developing TPC, RICH and silicon ical calculations if they are to match to masses just beyond this, from 1 to Urša Rojec collider should 2 be done by using the provided library and Control Systems Tel +386 1 477 66 76 strip detectors, among others. She also experimental precision by the end of 1000 GeV/c . C a rl o s d e l o s He r o s o f U p p s a l a HMI screens. Email [email protected] pointed out that although 80% of R&D succeed the HL-LHC’s run, showcasing work to University explained that experiments Engineer s Project Manager Web www.cosylab.com s p e c i a l i s t s b e l i e v e t h e i r w or k h a s p o t e n- the LHC extend next-to-next-to-leading order such as XENON1t are pushing close to

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FIELD NOTES HIGH VOLTAGE. EXACTLY.

the so-called neutrino floor, and advo- success of the ΛCDM model to describe The magic of for t h e d i s c o v e r y o f t h e t o p q u a r k, a n d t h e POWER FOR MODERN DETECTORS cated for the development of directional t h e u n i v e r s e i n j u s t s i x p a r a m e t e r s, w it h the cosmic W M A P a n d Pl a n c k c ol l a b or a t i o n s for t h e i r detection methods that can distinguish François Bouchet of the Institut d’As- outstanding contributions to astropar- microwave MODULAR LOW AND HIGH VOLTAGE MULTICHANNEL POWER SUPPLY SYSTEMS s ol a r n e ut r i n o s f r o m W I M P s, a n d plu n g e trophysique de Paris declaring that “the ticle physics and cosmology. Today’s into what is rat her a neut rino “sw amp”. magic of the cosmic microwave back- background is challenges are arguably even greater, An exciting synerg y bet ween heav y- ground is not dead”, and explaining that not dead and the spirit of EPS-HEP 2019 was to MMS MMS ion physics and gravitational waves Pl a n c k d a t a h a v e r u l e d o ut s e v e r a l m o d e l s r e j e c t a f a l s e e q u i v a l e n c e b e t w e e n p h y s i c s HV LV was in evidence, with the two disparate of inflation. Interdisciplinarity was also being “new” and being beyond the SM. compatible compatible approaches both now able to probe the o n d i s pl a y i n r e p or t s o n m u l t i-m e s s e n g e r P a r t i c i p a nt s’ hu n g e r for t h e t e c h n ol o g i c a l e q u a t i o n o f s t a t e o f nu c l e a r m a t t e r. P a r- astronomy, with particular excitement innovation required to answer the many t i c u l a r e m p h a s i s w a s pl a c e d o n t h e n e e d r e s e r v e d for t h e pr o p o s e d E u r o p e a n-l e d remaining open questions was matched to marry the successful hydrodynam- Einstein Telescope gravitational-wave b y a n o p e n n e s s t o r e c o n s id e r t h e or e t i c a l ical and statistical description of ion– observatory, which Marek Kowalski of thinking on fine tuning and naturalness, ion collisions with that used to describe DESY reported will most likely be built a n d h o w t h e s e pr i n c i pl e s i n for m t h e f u r- proton–proton collisions, especially in either Italy or the Netherlands, and ther exploration of the field. in the tricky proton-ion regime. These that will boast 10-times better sensitivity EPS-HEP 2021 will take place in efforts are already bearing fruit in jet than current instruments. Hamburg from 21–28 July. modelling. On the cosmological side, This year’s EPS prize ceremony speakers reflected on the enduring rewarded the CDF and D0 collaborations Mark Rayner CERN.

Higgs Hunting 2019 Higgs hunters still hungry in Paris a rd a Fay L The 10th Higgs Hunting workshop took pl a c e i n O r s a y a n d P a r i s f r o m 29–31 Ju l y, a t t r a c t i n g 1 10 p h y s ic i s t s for l i v e l y d i s c u s- sions about recent results in the Higgs sector. The ATLAS and CMS collabora- tions presented Run 2 analyses with up to 140 fb–1 of data collected at a centre- o f-m a s s e n e r g y o f 13 TeV. T h e s t a t i s t i c a l uncertainty on some Higgs properties, highest channel density to save valueable installation space such as the production cross section, has now been reduced by a factor three best ripple and noise characteristics c o m p a r e d t o R u n 1. T h i s p ut s s o m e H i g g s s t u d i e s o n t h e v e r g e o f b e i n g d o m i n a t e d by systematic uncertainties. By the end up to 30 kV, up to 100 W per channel of the LHC’s programme, measurements o f t h e H i g g s c o u pl i n g s t o t h e p h o t o n, W, pure LV compatible, pure HV compatible and mixed setup crates available Z, gluon, tau lepton and top and bottom f r o m AT L A S a n d S u z a n n e G a s c o n-S h o t k i n Looking up high precision, he continued, and all q u a r k s a r e a l l e x p e c t e d t o b e d o m i n a t e d from CMS described direct searches for Some Higgs but three of them are linked to Higgs- high class & quality precision low and high voltage supplies by theoretical rather than statistical or such additional Higgs bosons decaying measurements are boson interactions. experimental uncertainties. to SM particles or Higgs bosons. Loan on the verge of Hunting season may now be over, interchangeable controller boards for networking and software control Several searches for additional Higgs Truong from ATLAS and Yuri Gershtein being systematics C e r ut t i c o n c lu d e d, b ut t h e t i m e t o s t u d y bosons were presented. The general from CMS described studies of rare – dominated. the anatomy of the Higgs and exploit the recipe here is to postulate a new field and potentially beyond-SM – decays of 95% of LHC data still to come is close in addition to the Standard Model (SM) the 125 GeV Higgs boson. No significant at hand. Giulia Zanderighi’s theory FLEXIBLE CHANNEL H i g g s d o u bl e t, w h i c h i n t h e m i n i m a l c a s e e x c e s s e s w e r e r e p or t e d, b ut h o p e r e m a i n s summary had a similar message: Higgs COMBINATIONS yields a lone physical Higgs universally for Run 3, whic h w ill beg in in 2021. studies are still in their infancy and the BY MODULAR associated with the particle discovered Nobel laureate Gerard ’t Hooft gave a discovery of what seems to be a very CHANNELS a t t h e L HC w it h a m a s s o f 1 25 G eV i n 201 2. historical talk on the role of the Higgs SM-like Higgs at 125 GeV allows us to Adding a hypothetical additional Higgs in the renormalisation of electroweak e x pl or e a n e w s e c t or w it h a br o a d e x p e r- doublet, however, as in the two Higgs theory, recalling the debt his Utrecht i m e nt a l pr o g r a m m e t h a t w i l l e x t e n d o v e r doublet model, would yield five physical group, where the work was done almost decades. She concluded with a quote from states: CP-even neutral Higgs bosons h 50 y e a r s a g o, o w e d t o pi o n e e r s l i k e Fa d- A br a h a m L i n c ol n: “G i v e m e s i x h o u r s t o and H, the CP-odd pseudoscalar A, and deev and Popov. Seven years after the c h o p d o w n a t r e e a n d I w i l l s p e n d t h e fi r s t OPC-UA, SNMP t w o c h a r g e d H i g g s b o s o n s H ±; t h e m o d e l p a r t i c l e’s d i s c o v e r y, w e n o w k n o w it t o b e four shar pening t he a xe.” w o u l d a l s o b e q u e a t h t h r e e a d d it i o n a l f r e e s pi n-0 w it h m a i n l y C P- e v e n i nt e r a c t i o n s T h e n e x t H i g g s Hu nt i n g w or k s h o p w i l l parameters. Other models discussed at with bosons, remarked Fabio Cerutti of be held in Orsay and/or Paris from 7–9 Higgs Hunting 2019 include the minimal B e r k e l e y i n t h e e x p e r i m e nt a l s u m m a r y. September 2020. NEW EHS FLEX HV Boards High Class Low Voltage Boards Controller Boards with Linux inside integrated EPICS IOC, SNMP, and next-to-minimal supersymmetric With precision on the Higgs mass now High Voltage Supply highly up to 16 channel LV for on site customizable through plug- frontend hardware supply saves OPC-UA and Webservices, SMs and extra Higgs states with doubly b e t t e r t h a n t w o p a r t s p e r m i l l e, a l l o f t h e Louis Fayard Laboratoire de gable channels (by factory) cable and installation space also „bare metal“ use c h a r g e d H i g g s b o s o n s. A n n a K a c z m a r s k a SM’s free parameters are known with l’Accélérateur Linéaire.

20 CERN COURIER SEPTEMBER/OCTOBER 2019 WWW.WIENER-D.COM | WWW.ISEG-HV.COM/MMS

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FIELD NOTES FIELD NOTES

PlancK 2019 Workshop on Atomic ExpErimEnts for DArk m AttEr AnD Gr Avity Explor Ation Between desert and swampland Interdisciplinary physics at the AEDGE Following the discovery of gravitational MAGIA-advanced in Italy, AION in the J Illana 10–19 At the 22nd edition of the Planck con- Higgs vacua could lead to violent phe- waves by the LIGO and Virgo collabora- LISA UK and ELGAR in France. Delegates ference series, which took place in Gra- nomena in the early universe that might tions, there is great interest in observing 3 also heard about space – CACES (China) –20 6 × 10 M nada, Spain, from 3–7 June, 170 particle be tested by future gravitational-wave other parts of the gravitational-wave 10 10y and CAL (NASA) – and sounding-rocket year day physicists and cosmologists discussed detectors. Within the inflationary uni- spectrum and seeing what they can tell month hour experiments – MAIUS (Germany) – using 10–21 the latest in beyond the Standard Model verse these phenomena might also lead to us about astrophysics, particle physics AEDGE LIGO cold atoms in space and microgravity. (BSM) physics and ultraviolet comple- the production of primordial black holes and cosmology. The European Space ESA has recently issued a call for white 10–22 600M tions of the SM within theories that unify that could explain dark matter. Agency (ESA) has approved the LISA papers for its Voyage 2050 long-term sci- characteristic strain the fundamental interactions. Discussions of ultraviolet (i.e. high- space experiment that is designed to ET ence programme, and a suggestion for an 10–23 Several speakers addressed the serious energy) completions of the SM encom- observe gravitational waves in a lower atom interferometer using a pair of sat- model-building restrictions in supersym- passed the grand unification of funda- frequency band than LIGO and Virgo, 10–24 ellites is being put forward by the AEDGE metry and Higgs compositeness that are mental interactions, the origin of neutrino while the KAGRA experiment in Japan, 10–4 10–3 10–2 10–1 100 101 102 103 team (in parallel with a related sugges- imposed by the negative results of direct Modular BSM physics. On the cosmological side, masses, flavour symmetries and the the INDIGO experiment in India and the frequency [Hz] tion called STE-QUEST) to build upon the searches for BSM particles at ATLAS and invariance delegates learned of the latest attempts so-called “swampland conjectures”, proposed Einstein Telescope (ET) will experience with prior experiments. AEDGE CMS. Particular emphasis was put on the Ferruccio Feruglio to build models of WIMPs, axions, mag- which characterise theories that might reinforce LIGO and Virgo. However, there interferometers offer interesting pros- Frequency niche was the focus of the CERN workshop, and (extended) Higgs sector of the SM, where of INFN Padova netic relics and dark radiation, which also not be compatible with a consistent the- is a gap in observational capability in pects for detecting some candidates for AEDGE could would have unique capabilities to probe the precision measurements might detect sig- ponders predictivity include mechanisms for baryogenesis and ory of quantum gravity. Therefore, one the intermediate-frequency band where ultra-light dark matter as well as gravi- observe the infalls assembly of the super-massive black holes nals of BSM physics. Updates from LHCb in the neutrino inflat ion in t he early universe. might hope that healthy signals of BSM there may be signals from the mergers of tational waves in the mid-frequency gap. and mergers of known to power active galactic nuclei, and Belle on the flavour anomalies were sector. Given the absence of new BSM parti- physics might appear somewhere between massive black holes weighing between In particular, a possible space experi- binary massive physics beyond the Standard Model in also eagerly discussed, with proposed cles so far at the LHC, theorists talk of the desert and the swampland. 100 and 100,000 solar masses, and from ment called AEDGE could complement black holes. The toy the early universe and ultra-light dark explanations including leptoquarks and a “desert” beyond the weak and Planck Planck 2020 will be held from 8-12 June a first-order phase transition or cosmic the observations by LIGO, Virgo, LISA and models correspond matter. AEDGE would be a uniquely inter- additional U(1) gauge symmetries with scales containing nothing but SM par- in Durham, UK. strings in the early universe. other approved experiments. to a redshift z = 2. disciplinary space mission, harnessing exotic vector-like quarks. However, not ticles. Several speakers reported that This was the motivation for a work- The workshop shared information cold-atom technologies to address key all were convinced that the results signal phase transitions between non-trivial Hans Peter Nilles University of Bonn. shop held at CERN on 22 and 23 July that about long-baseline terrestrial cold- issues in fundamental physics, astro- brought experts from the cold-atom atom experiments that are already physics and cosmology. Humboldt Kolleg Humboldt Humboldt Kolleg conference lattice field theory that is theoretically community together with particle funded and under construction, such Particle physics d i ffic u l t t o s ol v e a n d m a p s it o nt o a fuly physicists and representatives of the as MAGIS in the US, MIGA in France Oliver Buchmueller Imperial College controllable quantum system such as an gravitational-wave community. Exper- and ZAIGA in China, as well as ideas for London, Albert De Roeck CERN and meets gravity in the optical lattice that can be programmed iments using cold atoms as clocks and in future terrestrial experiments such as John Ellis King’s College London. in experiments to do calculations – a Austrian Alps quantum simulator. First promising fcc WEEk 2019 N Lobet technological readiness of the FCC-ee, results with up to 20 qubits have been Study comes full which could be operational by the end The Humboldt Kolleg conference obtained for the Schwinger model (QED of the 2030s and therefore allow time to Discoveries and Open Puzzles in Parti- in 1+1 dimensions). This model exhibits EuroCirCol develop the novel technologies required cle Physics and Gravitation took place d y n a m i c a l m a s s g e n e r a t i o n a n d i s a fi r s t for a 100 TeV proton–proton collider. at Kitzbühel in the Austrian Alps from prototype before looking at more com- More than 400 researchers convened in In his keynote talk, Nima Arkani- 24 to 28 June, bringing Humboldt prize plicated theories like QCD. Brussels from 24 to 28 June for the annual Hamed of the Institute for Advanced winners, professors and research-fellow A key puzzle concerns the hierarchies meeting of the Future Circular Collider Study highlighted the importance of alumni together with prospective future of scales: the small ratio of the Higgs- (FCC) study. In addition to innovations scrutinising the Higgs boson at a post- fellows. The meeting was sponsored by ogy of a carpet: it looks flat and invar- Lofty thinking boson mass to the Planck scale plus the in superconductivity, high-field mag- LHC machine. Speakers also stressed the the Humboldt Foundation, based in Bonn, iant under translations when viewed Humboldt Kolleg very small cosmological constant that nets, superconducting radio-frequency c o m pl e m e nt a r it y b e t w e e n t h e d i ffe r e nt whose mission is to promote coopera- from a distance, but this smoothness participants at the drives the accelerating expansion of systems and civil-engineering studies, FCC options in searching for dark-matter tion between scientists in Germany and dissolves when we look at it close up, Hotel Kaiserhof in the universe. Might these be related? discussions sought to clarify issues sur- Brussels clout and an increase in the critical current candidate particles and other new phys-

elsewhere. The programme focused on e.g. as perceived by an ant crawling on Kitzbühel. The cosmological constant is related rounding the physics research topics that CERN Director- density of Nb3Sn wire, promise to signif- ics. Finally, the potential for studying connections between particle physics and it. A critical system close to the Planck to the vacuum energy density, which FCC can address. General Fabiola icantly reduce the costs of exploring the the strong interaction with heavy-ion the large-scale cosmological structure scale – the scale where quantum- is in turn connected to possible phase T h e m e e t i n g a l s o m a r k e d t h e fi n a l e v e nt Gianotti at high-energy frontier and could find prac- collisions, and detailing parton distri- of the universe. gravity effects should be important – transitions in the early universe. Future of the Horizon 2020 EuroCirCol project FCC Week 2019. tical applications outside particle physics. bution functions with a proton–electron The most recent LHC experimental could behave similarly: the only modes gravitational-wave experiments with – a European Union project to produce The four-volume FCC conceptual design interaction point, were demonstrated. results were presented by Karl Jakobs that can exist as long-range correlations, LISA were discussed by Stefano Vitale a conceptual design study for a post- report was also presented. Authored The sustainability of research infra- (Freiburg and ATLAS spokesperson), e.g. light-mass particles, self-organise (Trento) and are expected to be sensitive LHC research infrastructure based on an by 1350 people from 150 institutes, the structures and the assessment of their confirming the status of the Standard into multiplets with a small number of t o t h e e ffe c t s o f t h e s e p h a s e t r a n s it ions. energy-frontier 100 TeV circular hadron report “underlines the global attractive- societal impact were other highlights Model (SM). A key discussion topic raised particles, just as they do in the SM. The A main purpose of Humboldt Kolleg is collider. Since June 2015 the project has ness of the FCC and documents the far- of FCC week 2019, as discussed at a spe- by Fred Jegerlehner (DESY-Zeuthen) is vector modes become the gauge bos- the promotion of young scientists from produced a wealth of results in high-tech reaching benefits that the project can cial “Economics of Science” workshop. whether the SM’s symmetries might be ons of U(1), SU(2) and SU(3); low-energy the central European region. Student domains via the collaborative efforts of have for Europe and future generations,” E x p e r t s f r o m t h e fie l d o f e c o n o m i c s s h a red “emergent” at the relatively low energies symmetries such as baryon- and lep- poster prizes sponsored by the Kitzbühel partners in Europe and other countries said Frédérick Bordry, CERN director for lessons learned with representatives from of current experiments: in contrast to ton-number conservation would all be mayor Klaus Winkler were awarded to such as the US, Japan, Korea and Russia. accelerators and technologies. CERN and other research organisations, unification models that exhibit maxi- violated close to the Planck scale. Janina Krzysiak (IFJ PAN, Krakow) and These include impressive progress toward A wide range of talks focused on a including SKA, ESA and ESS, demonstrat- mal symmetry at the highest energies, Ideas connecting particle physics and Jui-Lin Kuo (HEPHY, Vienna). 16 T magnets and in the performance of future circular lepton collider (FCC-ee) ing the many benefits beyond physics that the gauge symmetries could emerge quantum computing were also discussed superconducting wires. Breakthroughs as the first step of the FCC programme, major international projects bring. in the infrared, but “dissolve” in the by Peter Zoller (Innsbruck) and Erez Steven Bass Kitzbühel Centre for Physics, in both fields, such as a first accelera- followed by an energy-frontier proton extreme ultraviolet. Consider the anal- Zohar (MPQ, Munich). Here, one takes a Austria. tor-type magnet exceeding 14 T (see p7) collider (FCC-hh). Results testify to the Panos Charitos CERN.

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CCSepOct19_Fieldnotes_v3.indd 22 29/08/2019 09:32 CCSepOct19_Fieldnotes_v3.indd 23 29/08/2019 09:35 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM CERNCOURIER.COM Ultra High Performance FIELD NOTES FIELD NOTES Silicon Drift Detector

® FAST SDD Str angeneSS in Quark M atter g-2 physics week Count Rate = >1,000,000 CPS Quark-matter mysteries on the run in Bari Muon g−2 collaboration prepares for first results D Elia

The True State-of-the-Art The annual “g-2 physics week”, which took in both frequencies. The absolute values of the to publishing its first result with a precision place on Elba Island in Italy from 27 May to two frequencies are still subject to a ~25 ppm better than E821 towards the end of the year. • New in-house manufacturing 1 June, saw almost 100 physicists discuss the hardware blinding offset, so no physics con- • Lower noise latest progress at the muon g−2 experiment at clusion can yet be drawn. But the exercise has Marco Incagli and Graziano Venanzoni Fermilab. The muon magnetic anomaly, a , is shown that the collaboration is well on the way INFN Sezione di Pisa . • Lower leakage current μ Anz_spec_CERN_8-2019_sp 02.08.19 12:45 Seite 1 one of the few cases where there is a hint of a • Better charge collection discrepancy between a Standard Model (SM) prediction and an experimental measurement. Compatible with EPICS tools & libraries Almost 20 years ago, in a sequence of increas- ingly precise measurements, the E821 collabo- 2 55 25 mm FAST SDD® Fe Spectrum Golden age SQM 2019 highlighted the fast pace of developments in heavy-ion research. ration at Brookhaven National Laboratory (BNL) 25 mm2 FAST SDD® 800,000 230K, Tpk = 8 µs 1,000,000 determined aμ = (g–2)/2 with a relative precision Peak to 1 keV background Mn Kα The XVIII International Conference on created in different stages of the system’s of 0.54 parts per million (ppm), providing a rig- 26,000:1 100,000 Mn Kβ Strangeness in Quark Matter (SQM 2019) was evolution. Further studies and future meas- orous test of the SM. Impressive as it was, the 600,000 10,000 held from 10 to 15 June in Bari, Italy. With urements may be needed. result was limited by statistical uncertainties. Generate 270 delegates from 32 countries, the largest A promising new perspective for the LHC COUNTS 400,000 122 eV FWHM 1,000 participation ever for the SQM series, the data is to use high-energy pp and p-Pb col- up to 8 signals 100 conference focused on the role of strange and l i s i o n s a s f a c t or i e s o f i d e nt i fie d h a d r o n s c re- P Girotti 200,000 h e a v y-fl a v o u r q u a r k s i n h e a v y-i o n c ol l i s i ons ated by a source of finite radius and then to 10 a n d a s t r o p h y s ic s. T h e s c ie nt i fic pr o g r a m m e measure the ensuing interactions between

0 1 consisted of 50 invited plenary talks, 76 these hadrons using femtoscopy. This tech- 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 Energy (keV) contributed parallel talks and a rich poster nique has allowed the ALICE collaboration M2p.65xx session with more than 60 contributions. to study interactions that were so far not 8 variations Resolution vs Peaking Time 180 A state-of-the-art session opened the con- measured at all and probe, for instance, the 25 mm2 ference, also including a tribute to the late p-Ξ and p-Ω interaction potentials. These Ethernet 170 Roy Glauber entitled “The Glauber model in results provide fundamental constraints to

160 Standard SDD high-energy nucleus–nucleus collisions”. the QCD community and are significant in DN2.65x Subsequent sessions were dedicated to high- the context of the astrophysics. 6 variations ® 150 FAST SDD lights from theory and experiment, and Ne w r e s u l t s o n t h e o n s e t o f d e c o n fi n e m e nt included reports on results from low- and were shown by the NA61/SHINE collaboration. 140 high-energy collisions, as well as on hyperon First results on strangeness production at low Fuzzy physics The “Elba vacuum polarisation” on (eV FWHM @ 5.9 keV) @ 5.9 FWHM on(eV ti 130 interactions in lattice QCD and thermal mod- energy from HADES and BM@N also enriched represents the missing piece in the muon’s Resolution (eV FWHM @ 5.9 keV) Resolu els. Representatives from all major collabo- the discussion at SQM 2019. anomalous magnetic moment. 120 0.000 1.00 1 2.00 2 3.00 3 4.00 4 5.00 5 rations at CERN’s LHC and SPS, Brookhaven’s Presentations at the final session showed Peaking Time (μs) Peaking Time (µs) RHIC, the Heavy Ion Synchrotron SIS at the good prospects for future measurements at A n e w m u o n g−2 e x p e r i m e nt c u r r e nt l y t a k i n g Generate GSI Darmstadt and the NICA project at the FAIR (GSI Darmstadt), NICA (JINR Dubna), data at Fermilab, called E989, aims to improve Options: JINR Dubna made special efforts to release the Heavy-Ion Project (J-PARC), and at t h e e x p e r i m e nt a l e r r or o n a μ by a factor of four. up to 16 signals new results at SQM 2019. CERN, given ongoing detector upgrades, the The collaboration took its first dataset in 2018, • 25 mm2 active area collimated to 17 mm2 Among the highlights were reports that high-luminosity programme, and possible integrating 40% more statistics than the BNL 2 2 • 70 mm collimated to 50 mm particle-yield measurements are close to next-generation colliders. Perspectives for e x per iment, and is now coming to t he end of a • Windows: Be (0.5 mil) 12.5 µm, or determining where phenomena such as QCD measurements at future electron–ion second run that will yield a combined dataset 16 bit AWGs with 40 or 125 MS/s C Series (Si3N4) strangeness enhancement are localised in colliders were also presented. On the theory more than three times larger. phase space. Collective behaviour in small side, new developments and strong research A t h or o u g h r e v ie w o f t h e m a n y a n a l y s i s e ffor t s Precise test signals from DC to 60 MHz • TO-8 package fits all Amptek configurations systems was also a much-discussed topic, efforts are bringing a better understanding during the first data run has been conducted. • Vacuum applications with new results from the PHENIX experi- of strangeness production and open heavy- The muon magnetic anomaly is determined from 700 MByte/s FIFO streaming (PCIe) ment showing that p-Au, d-Au and 3He-Au flavour dy namics in heav y-ion collisions. the ratio of the muon and proton precession collisions exhibit elliptic flow coefficients Young scientist prizes sponsored by the f r e q u e n c i e s i n t h e s a m e m a g n e t i c fie l d. T h e u lti- consistent with expectations regarding Nuclear Physics European Collaboration mate aim of experiment E989 is to measure both their initial collision geometry. Results Committee were awarded to Bong-Hwi Lim of these frequencies with a precision of 0.1 ppm from ALICE, CMS and STAR consistently of Pusan National University, Korea, and to by employing techniques and expertise from SPECTRUM corroborate t he presence of elliptic flow in Olga Soloveva of Goethe University, Frankfurt particle-physics experimentation (straw track- INSTRUMENTATION small systems. for their poster contributions. The inaugural ing detectors and calorimetetry), nuclear physics There is also increasing interest in Andre Mischke Award (established at SQM2019) (nuclear magnetic resonance) and accelerator Perfect fit – modular designed solutions transverse-momentum differential for the young scientist with the best experi- science. These frequencies are independently 40 Years of b a r y o n-t o -m e s o n r a t io s i n t h e h e a v y-fl a v o u r mental parallel talk was given to Erin Frances measured by several analysis groups with differ- Products for Your Imagination sector. Recent results from pp and Pb-Pb col- Gauger of the University of Texas, Austin. e nt m e t h o d ol o g ie s a n d d i ffe r e nt s u s c e p t i bi l it i e s Europe / Asia: Phone +49 (4102) 695 60 | US: Phone (201) 562 1999 lisions from both ALICE and CMS suggest that The next edition of SQM will take place in to systematic effects. ® AMPTEK Inc. the same dynamics observed in the ratio Λ/K0 Busan, Korea, in May 2021. A recent relative unblinding of a subset of S www.spectrum-instrumentation.com [email protected] may be present in Λc/D, despite the fact that the data with a statistical precision of 1.3 ppm www.amptek.com strange and charm quarks are thought to be Domenico Elia INFN Bari. s h o w e d e x c e l l e nt a g r e e m e nt a c r o s s t h e a n a l y s e s

24 CERN COURIER SEPTEMBER/OCTOBER 2019 CERN COURIER SEPTEMBER/OCTOBER 2019 25

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FEATURE TUNNEL ENGINEERING FEATURE TUNNEL ENGINEERING Z Arenas

Fig. 1. The scale of 3 TeV LHC the proposed CLIC FCC and FCC projects 1.5 TeV CLIC would dwarf limestone Jura CERN’s existing molasse infrastructure, 380 GeV molasse LHC making them some CLIC subalpine IP of the largest Lake Geneva 380 GeV Exp. tunnelling projects point FCC Exp. Prealps prevessin site point in the world. Exp. 1.5 TeV point

3 TeV Vuache

Saleve Arve Rhône Valley Valley Breakthrough

New service Exp. point tunnels for the Prealps Fig. 2. The FCC would be made of a series of straight sections and high-luminosity Mandallaz curves, with numerous shafts, caverns and adits. LHC being excavated at reason for this is the sensitivity of the equipment inside. On top of the molasse sits a softer soil, called the moraines, Point 5 in July. Digging a 5.6 m-diameter hole disturbs rock that has been which is made up of more recent, unconsolidated glacial there for millennia, causing it to relax and to move. Modern deposits. The Jura itself is made of limestone rock, which tunnelling techniques can control these movements and while competent, is soluble and can form a network of get a tunnel to within a few centimetres of its intended underground voids, known as karsts. design. For example, the two ends of the 27 km LEP ring We can never fully understand the ground before we came together with just 1 cm of error. It would be impos- start tunnelling and there is always the risk of encoun- sible to achieve the nanometre-level tolerances that the tering something unexpected, such as water, faults or beamline requires, so the sensitive equipment installed in obstructions. These cost money to overcome and/or delay a completed accelerator tunnel must incorporate adjustable the project; in the worst cases, they may even cause the alignment systems into their designs. tunnel to collapse. To help mitigate these risks and provide TUNNELLING The city of Geneva sits on a large plateau between the technical information for the tunnel design, we investigate Jura and Prealps mountains. The bedrock of the plateau is the ground in the early stages of the project by drilling a competent (resistant to deformation) sedimentary rock, boreholes and testing ground samples. Like most things in called molasse, which formed when eroded material was civil engineering, however, there is a balance between the FOR PHYSICS deposited and consolidated in a basin as the Alps lifted up. cost of the investigations versus the risks they mitigate. CERN’s tunnel optimisation tool

Surveying the geological, environmental and technical In 2014, with the help of UK-based constraints of a post-LHC collider. engineering consultancy Arup, CERN developed the tunnel optimisation tool (TOT) to integrate project requirements and n 2012 the CERN management asked a question: what the Swiss Alps. Designing large infrastructure like the data into a geospatial model. The is the largest circular machine that could be feasi- FCC tunnel requires the collection and interpretation of web-based tool allows the user to digitally Ibly constructed in the Geneva region from a civil- numerous data, which have to be balanced for the optimum move the FCC tunnel, change its size, shape engineering perspective? Teams quickly embarked on an level of risk, cost and project requirements. and depth and see, in real-time, the impacts extensive investigation of the geological, environmental T h e fi r s t a n d m o s t i m p or t a nt t a s k i n d e s i g n i n g t u n nelsi of the changes on the design. Geology, and technical constraints in pursuit of the world’s largest to understand the needs and requirements of the users. For surface constraints and environmentally accelerator. Such a machine would be the next logical step road or rail tunnels, this is relatively straightforward. For protected areas are visualised, and in exploring the universe at ever smaller scales. a cutting-edge scientific experiment, multi-disciplinary parameters such as plane inclinations and Since construction of the 27 km circumference Large working groups are needed to identify the key criteria. The tunnel depth can be changed at the click of a Hadron Collider (LHC) was completed in 2005, CERN has diameter of a new tunnel depends on what components mouse. The tool warns users if certain limits been looking at the potential layouts for the tunnels that would be inside – ventilation systems, magnets, lighting, are exceeded or obstacles are encountered, will house the next generation of particle accelerators. transport corridors, etc – so they can fit in like a jigsaw. for example, if a shaft is in the middle of Lake The Compact Linear Collider (CLIC) and the Future Circular THE AUTHORS Geneva! When it was built, TOT was the first changing requirements to ultimately deliver in Japan. Recently, a TOT was built by Arup of its kind within the industry. It has cut a better project. The success of TOT led to its to quickly and cheaply assess a range of Collider (FCC) are the two largest projects under consider- John Osborne, Bespoke designs the cost of the civil-engineering design and replication for CLIC and the International alignments for a 3 km tunnel under the ation. With a circumference of 100 km, the FCC will require Alexandra Tudora Unlike other tunnelling projects, there are no standard rules one of the world’s largest tunnels – almost twice as long and Ben Swatton or guidance for the design of particle-accelerator tunnels, has provided us with the flexibility to meet Linear Collider (ILC) under consideration ancient Stonehenge heritage site in the UK. as the recently completed 57 km Gotthard Base Tunnel in CERN. meaning each design is, to a large extent, bespoke. One

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FEATURE TUNNEL ENGINEERING

No boreholes have been sunk specifically for FCC yet, but depth below we have access to a substantial amount of data from the lake surface LHC and from the Swiss and French authorities. 0 m T h e a n s w e r t o C E R N’s q ue s t io n i n 201 2 w a s t h at a (q u a s i-) c i rc u l a r t u n n e l up t o 100 k m lo n g c o u ld b e b u i lt n e a r G e n e v a 45–50 m Exciting Innovations for Research Scientists (figure 1). This will be confirmed with further site inves- immersed tube tunnel superficial sediments tigations to verify the design assumptions and optimise a 85–90 m layout for the new machine. The FCC study considers two Mixshield TBM The VORTEX® ME-7 SDD potential high-energy accelerators: hadron–hadron and 150–180 m moraines electron–positron, and the FCC would consist of a series open shield TBM 2 7 x 50 mm SDD sensors in a probe diameter of 38.1 mm of arcs and straight sections (figure 2). Depending on the molasse choice of a future collider, civil-engineering designs for FCC a n d /or C L IC w i l l n e e d t o b e d e v e lo p e d f u r t h e r. A lt h o u g h t h e challenges between the two studies differ, the processes and tools used w ill be similar. c i v i l e n g i n e e r s t o d i s c a rd t h e Ju r a o p t io n. M i n i n g t h r o u g h Fig. 3. Modern the karstic limestone caused several delays and costly technology presents Optimising the alignment repairs after water and sediment flowed into the tunnel different options Ha v i n g d e t e r m i n e d t h e FC C’s fe a s i bi l it y, C E R N’s c i v i l e n g i- (see p39). To this day, intensive maintenance works are for tunnelling neers started designing the optimal route of the tunnel. n e e d e d b e t w e e n s e c t or s 3 a n d 4 o f t h e L HC t u n n e l a n d t h i s under Lake Geneva, Geology and topography are the key constraints on the tunnel h a s le d t o m a c h i n e s hut d o w n s l a s t i n g a s lo n g a s t w o w e e k s. which is one of the p o s it io n. T w o a l i g n m e nt o p t io n s w e r e u n d e r c o n s id e r at io n By 2016, the proposed length of the FCC had increased main constraints i n 201 2, b o t h 80 km long, one located under the Jura Moun- to b e t we en 80 a nd 100 km to achieve higher energies with on the alignment of tains and the other in the Geneva basin. When the FCC study two alignments under consideration: intersecting (which the FCC. VORTEX ME-7 SDD— 38 mm diameter offic i a l l y k ic k e d off i n 201 4, t h e y w e r e r e v ie w e d a lo ngsidea crosses the LHC in plan view) and non-intersecting. The 38 mm 47 km-circumference option fully excavated in the molasse. former is the current baseline design. The tunnel is located Detector - the same as the current E x p e r ie n c e o f t u n n e l l i n g t h r o u g h Ju r a l i m e s t o n e d u r i n g primarily in the competent molasse rock and avoids the VORTEX ME-7 SDD Rise Time Mapping VORTEX ME-4 SDD construction of the Large Electron Positron collider (LEP; pr o ble m at ic Ju r a l i m e s t o n e a n d t h e P r e a l p s. Ho w e v e r, it d o e s f r o m w h ic h t h e L HC i n h e r it e d m a n y o f it s t u n n e l s) c o n v i n c e d p a s s t h r o u g h t h e M a n d a l l a z l i m e s t o n e for m at io n a n d a l s o

AND Advances in civil engineering since the LEP days

It has been almost 35 years since three tunnel Herrenknecht to 40 m ahead and adjust their approach The VORTEX® 2mm thick SDD Sensor boring machines (TBMs) set off to carve out accordingly. Probe drilling and pre-support the 27 km-long hole that would house LEP measures can also be implemented from and, later, the LHC. Contrary to the recent within the machine, meaning that the mining claims of tech entrepreneur Elon Musk, the crew is safe and minimising delays to the technology used to construct modern tunnels construction programme. has been quietly and rapidly advancing For vertical shafts, the vertical shaft sinking since the construction of LEP, providing a machine and shaft boring machine are the faster, safer and more versatile way to build latest technological breakthroughs, taking tunnels. TBMs act as a mobile factory that all the technology of a TBM and standing it on simultaneously excavates rock from the face earth-pressure balance machines that use its end. The giant rig hangs off a crane and builds a tunnel lining from prefabricated the excavated soil to push back against the and excavates below the platform, whilst segments behind it. The outer shield of excavated face for support. Herrenknecht’s building a lining above it. The machine can the machine protects workers from falling Mixshield TBM (above) could be used to tunnel even work underwater to stabilise the shafts rock, making sure they are never working in the FCC under Lake Geneva, where water- during construction. unsupported ground. bearing moraines are encountered. Traditional tunnelling techniques, which One of the main advances in TBM technology Segmental linings can be constructed off- are useful for creating non-standard shapes is their ability to cope in variable ground site in a factory, improving quality, speed and or smaller tunnels like the experimental conditions. Most of the LEP tunnels were safety. The segments are assembled in the rear caverns in FCC, have come a long way, too. constructed in dry, competent rock, meaning of the TBM immediately after excavation. The These aren’t the normal sticks of dynamite the excavation face needed little support to segments can be fitted with a rubber gasket, you see in films or cartoons – highly stable stand up. Underneath the Jura Mountains, which provides a waterproof seal, eliminating explosives are slotted precisely in holes using however, pockets of water and soil form the need for the traditional secondary lining. a giant rig with multiple arms for speed. where the limestone dissolves into karsts. Across the 100 km of the FCC, this will lead to The electric detonators can be configured When a TBM hits this, the water can flow into substantial cost savings. to the millisecond for complex patterns of Contact us to discuss the future the tunnels, causing flooding and, at worst, Seismic and sonic scanners can be explosions that give tunnellers precise tunnel collapse. Modern TBMs come with a mounted to the front of the TBM, allowing control of the shape, speed and quality of

Hitachi High-Technologies Science America, Inc. www.hitachi-hightech.com/hhs-us/ variety of face-support measures, including operators to detect voids or obstacles up the excavation. 21770 Nordhoff St., Chatsworth, CA 91311 Email: [email protected] Tel: +1-818-280-0745 CERN COURIER SEPTEMBER/OCTOBER 2019 29

Untitled-2 1 03/05/2019 09:27 CCSepOct19_Tunnelling_v5.indd 29 29/08/2019 10:26 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM FEATURE TUNNEL ENGINEERING 300kW All Solid-State RF Amplifier

best arrangement for experimental and service caverns, Model : CA500BW2-8085RP A m b e r g E n g i n e e r i n g c a r r ie d o ut a s t r e s s a n a l y s i s (fi g u r e 4). R&K Company Limited R&K provides the world’s most reliable high performance solid-state RF Power Amplifiers. Although for data-acquisition purposes it is often desirable AMPLIFIER DESIGN to have the two caverns as close as possible to each other, the analysis showed that it would be prohibitively expensive to ・Consists of four (4) rack-mounted 75kW SSAs. build a 10 m concrete wall between the caverns. The cheaper ・Able to deliver 300kW via 4-way power combiner. option is to use the existing rock as a natural pillar, which ・96-way radial combiner for final power combining would require a minimum spacing of 45 m. of 75kW SSA. Tunnelling inevitably disturbs the surrounding area. ・Long-term & highly reliable operation achieved by protecting each final-stage transistor with The beamline of the LHC is incredibly sensitive and can built-in circulator at its output. detect even the smallest vibrations from the outside world. 96-way Radial Combiner Output Power Linearity ■Output Pulse 86 Frequency = 500MHz, Po = 300kW 85 This was a potential issue for construction works currently X：50μs / DIV Y：200mV / DIV 84 FWD LIMIT 83 82 taking place for the High-Luminosity LHC project. The 81 80 79 78 contractor had to improvise and modify a standard diesel 77 76 75 74 excavator with an electric motor to eliminate vibrations 73 72

Output Power (dBm) 71 Frequency 70 from the engine. The programme was also adapted so that 69 499MHz 68 500MHz 67 501MHz Fig. 4. Stress has to cross under Lake Geneva. To deal with the wealth of only the shafts were constructed during operation of the -15 -10 -5 0 5 10 Input Power (dBm) analysis of topographical, geological and environmental data relevant LHC, leaving the more disruptive cavern construction until ■Pulse Rise ■Pulse Fall Frequency = 500MHz, Po = 300kW Frequency = 500MHz, Po = 300kW separated (left) for a 100 km ring, CERN embarked on an innovative tunnel the start of the current shutdown. X：200ns / DIV Y：200mV / DIV X：50ns / DIV Y：200mV / DIV versus adjacent optimisation tool (TOT) that would let us assess a multitude SPECIFICATION Frequency Range : 500MHz 1MHz service and of alignment options in a fraction of the time (see “CERN’s Securing the future ± Output Power : 320kW @Peak, 300kW (min.) experimental tunnel optimisation tool”). CERN currently has 83 km of underground structures. The *Each rack-mounted amplifier section individually delivers 75kW. caverns. The alignment of the FCC tunnel has been optimised FCC would add over 100 km of tunnels, 3720 m of shafts, 26 (75kW/rack ×4 outputs) based on three key criteria at this stage: geology (building caverns (not including junction caverns), 66 alcoves and with Pulse Width : 1μs～300μs (max.) ～ in the competent molasse rock wherever possible); shaft up to 30 km between the Meyrin campus and the furthest Duty : 0 3% (max.) R&K Company Limited Operation Mode : Class AB depth (minimising the depth of shafts); and surface sites site. The estimated civil-engineering cost for FCC (carried www.rk-microwave.com AC Supply Input : AC200V±10%／3φ, 50／60Hz (choosing locations that minimise disruption to residents out by ILF Consulting Engineers) is approximately 6 billion 721-1 Maeda, Fuji-City, Shizuoka, 416-8577 Japan Size : (W)2240mm×(D)1300mm×(H)1510mm and the environment). S w i s s F r a n c s – 45% for t u n n e l s a n d t h e r e s t for s h a f t s, c a v- Tel:+81-545-31-2600 Fax:+81-545-31-1600 Email:[email protected] D e s pit e t h e b e s t e ffor t s t o a v oid t h e r i s k y Ju r a M o u nt a ins, erns and surface facilities – and benefits from significant the geology is not perfect. The Prealps region has complex, advances in tunnelling technology since the LEP-tunnel faulted geology and it is uncertain which layers the tunnel days (see “Advances in civil engineering since the LEP days”). will cross. Cracks or faults, caused by tectonic movements The safety of the underground areas is critical to ensure of the Alps and Jura, can occur in the molasse and lime- the safe and continued operation of the experiments, and stone. Excavation through Mandallaz limestone can lead CERN has developed advanced tools to inspect the struc- to similar issues encountered during LEP’s construction. t u r e s – s o m e o f w h ic h a r e m or e t h a n 60 y e a r s old. M a nu a l l y Large, high-pressure inflows can be difficult to remedy, inspecting the condition of the structures on the scale of the expensive and can create delays in the programme. FCC will become extremely challenging. We are therefore To minimise the depth of the shafts, the entire FCC ring developing new technologies that will allow us to monitor sits in an inclined plane with different heights above sea the condition of the tunnels remotely. Currently, teams are level around the tunnel. Modelling a range of alignment testing out how fibre-optic cables can be attached to the options at different locations and with different tunnel concrete linings to measure movements over time, and inclinations, constrained by the spacing requirements of developing and training algorithms to be able to spot and the experiments, it turned out that one shaft was 558 m characterise faults in the tunnel lining. In the future, the deep in the baseline design. The team therefore decided software will be able to measure these faults and compare to replace the vertical shaft with an inclined tunnel (15% the changes with previous inspections to assess how they slope) to pop out the side of the mountain. have progressed. To capture these images, a Tunnel Inspec- T h e pr e s e n c e o f L a k e G e n e v a i n flue n c e s t h e o v e r a l l d e pth t io n M a c h i n e, w h ic h r u n s o n t h e m o n or a i l i n t h e r o o f o f t h e of the FCC, and the tunnel optimisation tool tells us that LHC, and a floor-roving inspection robot have both been it isn’t possible to avoid tunnelling under the lake within tested to collect images and data, even when the tunnel is the study boundary. Modern tunnelling techniques open not safe for humans. These images can be rebuilt in a 3D up d i ffe r e nt o p t io n s for c r o s s i n g t h e l a k e, i n s t e a d o f s imply environment and viewed through a virtual-reality headset. digging deeper until we reach the rock (figure 3). Several Projects like the FCC and CLIC are not just exciting for options were considered, even including an option to build physicists. For civil engineers they represent challenges a hybrid particle accelerator-road tunnel in an immersed that demand new ideas and technology. At the annual World The presence tube tunnel (which was later scrapped because of poten- Tunnel Congress, attended by more than 2000 leading of Lake tial vibrations caused by traffic disrupting the beamline). tunnel and underground-space experts, CERN’s FCC has Geneva The current design compromises on a mid-depth tunnel already generated great interest. If approved, it would influences the passing through the permeable moraines on the lake bed. require the largest construction projects science has ever 614.891.2243 | www.lakeshore.com overall depth At the bottom of some of the FCC shafts are large exper- seen, bequeathing a tunnel that would serve fundamental of the FCC imental caverns with spans of up to 35 m. To determine the exploration into the next century. 

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FEATURE LEP’S PHYSICS LEGACY LEP’S ELECTROWEAK LEAP In t he aut um n of 1989 t he L a rge Elec t ron Posit ron col l ider (LEP) del ivered t he fi rst of se ver a l result s t hat st i l l dom i nate t he la ndsc ap e of pa r t ic le physics today.

n the early 1970s the term “Standard Model” did not yet exist – physicists used “Weinberg–Salam model” Iinstead. But the discovery of the weak neutral cur- rent in Gargamelle at CERN in 1973, followed by the pre- diction and observation of particles composed of charm quarks at Brookhaven and SLAC, quickly shifted the focus of particle physicists from the strong to the electroweak interactions – a sector in which trailblazing theoretical work had quietly taken place in the previous years. Plans for a n e le c t r o n–p o s it r o n c ol l id e r at C E R N w e r e s o o n b or n, with the machine first named LEP (Large Electron Posi- tron collider) in a 1976 CERN yellow report authored by a d i s t i n g u i s h e d s t ud y g r o up fe at u r i n g, a m o n g o t h e r s, Jo h n Ellis, Burt Richter, Carlo Rubbia and Jack Steinberger. L E P’s s i z e – fo u r t i m e s l a r g e r t h a n a n y t h i n g b e for e it – w a s chosen from the need to observe W-pair production, and to check that its cross section did not diverge as a function o f e n e r g y. T h e p h e n o m e n olo g y o f t h e Z-b o s o n’s d e c a y w a s n e ut r i n o s w a s w e l l e s t a bl i s h e d. S e v e r a l m o d e l-d e p e n d e nt OPAL fruits to come under similar scrutiny. At the time, the number of measurements from astrophysics and collider physics at the The OPAL logbook fermion families was undefined, and it was even possible time had pointed to the number of light active neutrinos entry for the first

that there were so many neutrino families that the Z line- (Nν) being less than five, but the SM could, in principle, Z boson seen at LEP, shape would be washed out. LEP’s other physics targets accommodate any higher number. recorded late on

included the possibility of producing Higgs bosons. At the The initial plan to measure Nν using the total width of 13 August 1989. t i m e, t h e m a s s o f t h e H i g g s b o s o n w a s c o m ple t e l y u n k n o w n the Z resonance was quickly discarded in favour of the and could have been anywhere from around zero to 1 TeV. visible peak cross section, where the effect was far more The CERN Council approved LEP in October 1981 for prominent – and in first approximation, insensitive to new c e nt r e-o f-m a s s e n e r g ie s up t o 1 10 G eV. It w a s a r e m a r k a ble possible detec table c ha n nels. The LEP e x per iments were vote of confidence in the Standard Model (SM), given that therefore thrown in at the deep end, needing to make an the W and Z bosons had not yet been directly observed. A absolute cross-section measurement with completely new frantic period followed, with the ALEPH, DELPHI, L3 and detectors in an unfamiliar environment that demanded OPA L d e t e c t or s a p pr o v e d i n 1983. B a s e d o n s i m i l a r g e o m e t r ic t r i g g e r s, t r a c k i n g, c a lor i m e t r y a n d t h e lu m i n o s it y m o n it or s principles, they included drift chambers or TPCs for the to all work and acquire data in synchronisation. m a i n t r a c k e r s, B G O c r y s t a l s, le a d–g l a s s or le a d–g a s s a n d- O n t h e e v e n i n g o f 13 A u g u s t, d u r i n g a fi r s t lo w-lu m i n o s it y wich electromagnetic calorimeters, and, in most cases, an pilot run just one month after LEP achieved first turns, i n s t r u m e nt e d r e t u r n yo k e for h a d r o n c a lor i m e t r y a n d muo n OPA L r e p or t e d t h e fi r s t o b s e r v at io n o f a Z d e c a y (s e e i mage filtering. The underground caverns were finished in 1988 a b o v e). E a c h e x p e r i m e nt q u ic k l y o b s e r v e d a h a n d f u l m or e. and t he detectors were in v arious stages of installat ion by The first Z-production run took place from 18 September to t he end of spr i ng 1989, by wh ic h t ime t he stor age r i ng had 9 O c t o b e r, w it h t h e fo u r e x p e r i m e nt s a c c u mu l at i n g a b o ut b e e n i n s t a l le d i n t h e 27 k m-c i rc u m fe r e n c e t u n n e l (s e e p39). 3000 visible Z decays each. They took data at the Z peak a nd at 1 a nd 2 GeV either side, improving the precision on THE AUTHORS Expedition to the Z pole t h e Z m a s s a n d a l lo w i n g a m e a s u r e m e nt o f t h e p e a k c r o s s Alain Blondel The first destination was the Z pole at an energy of around section. The results, including those from the Mark II col- LPNHE Paris, CERN 90 GeV. Its location was then known to ±300 MeV from l a b or at io n at SL AC’s l i n e a r e le c t r o n–p o s it r o n SL C c ol l id e r, and University of measurements of proton–antiproton collisions at Fermi- were published and presented in CERN’s overflowing main Geneva, Chiara lab’s Tevatron. The priority was to establish the number auditorium on 13 October. Mariotti INFN of light neutrino families, a number that not only closely Trailblazing events Clockwise from top left: OPAL spots the decay of a Z boson into two jets originating from a quark–antiquark pair; A f t e r o n l y t h r e e w e e k s o f d at a t a k i n g a n d 10,000 Z d e c a y s, Torino, Marco Pieri CERN and UC relates to the number of elementary fermions but also a pair of Z bosons decaying into two muons and two electrons in DELPHI; an L3 candidate for pair production of excited electrons decaying into the number of neutrinos was found to be three. In the San Diego, and i m p a c t s t h e c h e m ic a l c o m p o s it io n a n d l a r g e-s c a le s t r uc- an electron and a photon each; and a four-jet event recorded in 2000 by ALEPH that was a candidate for the associated production and decay of a Z and following years, some 17 million Z decays were accumu-

Pippa Wells CERN. t u r e o f t h e u n i v e r s e. B y 1989 t h e e x i s t e n c e o f t h e νe, νμ and ντ a Higgs boson into quark-antiquark pairs. lated, and cross-section measurement uncertainties fell

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FEATURE LEP’S PHYSICS LEGACY FEATURE LEP’S PHYSICS LEGACY

(a) (b) –0.032 (c) 6 (a) 0.4 (b) (c) 30 average measurements, 2ν mt = 178.0 ± 4.3 GeV theory uncertainty L3 LEP (5) LEP error bars increased mH = 114... 1000 GeV 4 Δαhad= 10 by factor 10 3ν 5 PETRA 0.02758 ± 0.00035 e+e–→ e+e–qq– 30 TRISTAN + – – 0.02749 ± 0.00012 3 e e → qq(γ) 2 0.3 10 e+e–→ μ+μ–(γ) –0.035 4 incl. low Q data 20 4ν mH

2

2 10 VI

(nb) 20 (pb) (Q)

g 3 s Δχ ww had α σ σ 0.2 10 m + – + – –0.038 t 2 cross section (pb) e e → W W 10 10 + – Δα e+e–→ ZZ I I + – + – + – 1 e e → W W γ YFSWW/RacoonWW e e + – + – 1 e e → γγ no ZWW vertex (Gentle) μ μ 0.1 + – QCD αs (Mz) = 0.1183±0.0027 e e → HZ only exchange (Gentle) + – –1 νe τ τ 68% CL excluded 10 mH = 115 GeV 0 –0.041 0 0 86 88 90 92 94 –0.503 –0.502 –0.501 –0.500 30 100 500 1 10 100 80 100 120 140 160 180 200 160 180 200 Ecm (GeV) gAl mH (GeV) Q (GeV) √s (GeV) √s (GeV)

Fig. 1. (a) Z-pole cross-section measurement from the four LEP experiments after seven years of running, establishing that the number of light neutrino Fig. 2. (a) The running of the strong coupling constant, measured both at LEP and in deep-inelastic-scattering experiments, as a function of the energy scale, families is equal to three. (b) Precision measurements at LEP, showing measurements of neutral-current lepton couplings for electrons, muons as predicted by QCD. (b) The LEP physics landscape, starting at the Z peak, above which the cross section is dominated by two-photon reactions (e+e– → and taus, and the average over the leptons, from the Z width, branching ratios and asymmetries (the purple arrow on the right represents the SM predictions e+e– qq– ). Other cross sections fall rapidly. The W and Z pair cross-sections become visible at 160 and 182 GeV. No Higgs boson was seen at LEP, excluding the mass without EW radiative corrections). (c) The data from the Z line shape and the direct searches predicted – assuming the Standard Model and nothing else – range from 15 MeV to 115 GeV. (c) The LEP ring was designed to test the cancellation of the various diagrams for WW production that arise in the electroweak a Higgs boson mass bet ween 115 GeV and 285 GeV at 95% confidence. The yellow region shows the direct exclusion from LEP. gauge theory. In the absence of electroweak unification, only the neutrino exchange diagram would be present, and the cross section would diverge.

to the per-mille level. And while the final LEP number – final Z-pole measurement, however, required the use of b e a m-e n e r g y m e a s u r e m e nt) t h at t h e fi n a l Z-p ole r e s u lt s the W and Z boson masses, the WW, then ZZ, production

Nν = 2.9840 ± 0.0082 – m a y a p p e a r t o b e a n e e d le s s l y pr e c i s e resonant depolarisation routinely during data taking. First were published a full 11 years later, constraining the Higgs diagrams open up (figure 2b). Accessing the W W thresh- m e a s u r e m e nt o f t h e nu m b e r t h r e e (fi g u r e 1 a), it t o d a y s e r v es a c h ie v e d i n 1991, t h i s t e c h n iq ue u s e s t h e n at u r a l t r a n s v e r s e m a s s t o b e le s s t h a n 2 85 GeV at 95% confidence level (figure old required the development of superconducting radio- as by far the best high-energy constraint on the unitarity spin polarisation of the beams to yield an instantaneous 1c), w it h a best fit at 129 G eV. f r e q ue n c y c a v it ie s, t h e fi r s t o f w h ic h w e r e a l r e a d y i n s t a lled of the neutrino mixing matrix. LEP’s stash of a million m e a s u r e m e nt o f t h e b e a m e n e r g y t o a pr e c i s io n o f ±0.1 MeV i n 1994, a n d t h e y e n a ble d a g r a d u a l i n c r e a s e i n t h e c e nt r e- clean tau pairs from Z → τ + τ–- decays also allowed the – so precise that it revealed minute effects caused, for From QCD to the W boson of-mass energ y up to a ma x imum of 209 GeV in 2000. u n i v e r s a l it y o f t h e le p t o n–n e ut r i n o c o upl i n g s t o t h e w e a k example, by Earth’s tides and the passage of local trains LEP’s fame in the field tends to concern its electroweak T h e “L E P 2” p h a s e a l lo w e d t h e e x p e r i m e nt s t o p e r for m a charged current to be tested with unprecedented preci- (s e e p40). T h e fi n a l pr e c i s io n w a s m or e t h a n 10 t i m e s b etr breakthroughs. But, with several million recorded hadronic s i g n at u r e a n a l y s i s, w h ic h d at e d b a c k t o t h e fi r s t c o n c e p t io n s ion. The pre s e nt a ve r a ge s a re s t i l l d om i n at e d b y t he L E P than had been anticipated in pre-LEP studies. Z decays, the LEP experiments also made big advances in of the machine: the measurement of the WW-boson cross

numbers: gτ/gμ = 1.0010 ± 0.0015 a n d g τ/ge = 1.0029 ± 0.0015. quantum chromodynamics (QCD). These results signifi- section. Would it diverge or would electroweak diagrams LEP continued to carry out Z-lineshape scans until 1991, Electroweak working group c a nt l y i n c r e a s e d k n o wle d g e o f h a d r o n pr o d uc t io n a n d q u a r k i nt e r fe r e t o s up pr e s s it? T h e pr e c i s e m e a s u r e m e nt o f t h e W W a n d r e p e at e d t h e m i n 1993 a n d 1995. T wo t h i rd s o f t h e t o t a l The LEP electroweak working group saw the ALEPH, DEL- and gluon dynamics, and drove theoretical and exper- cross section as a function of the centre-of-mass energy luminosity was recorded at the Z pole. As statistical uncer- PHI, L3 and OPAL collaborations work closely on com- imental methods that are still used extensively today. was a very important test of the SM since it showed that t a i nt ie s o n t h e Z’s p a r a m e t e r s w e nt d o w n, t h e e x p e r i m e nt s bined cross-section and other key measurements – in L E P’s a d v a nt a g e a s a le p t o n c ol l id e r w a s t o h a v e a n i n it i a l the sum and interference of three four-fermion processes were challenged to control systematic uncertainties, espe- p a r t ic u l a r t h e for w a rd-b a c k w a rd a s y m m e t r y i n le p t o n a n d state that was independent of nucleon structure func- were indeed acting in the WW production: the t-channel cially in the experimental acceptance and luminosity. Monte b-quark production – at each energy point. By 1994, results t io n s, a l lo w i n g t h e m e a s u r e m e nt o f a s i n g le, e n e r g y-s c a le- ν exchange, and the s-channel γ and Z exchange (figure Carlo modelling of fragmentation and hadronisation was from the SLD collaboration at SLAC were also included. dependent coupling constant. The strong coupling constant 2c). LEP data proved that the γWW and ZWW triple gauge

gradually improved by tuning to measurements in data. On D e t a i le d n e g o t i at io n s w e r e s o m e t i m e s n e e d e d t o a g r e e o n αs was determined to be 0.1195 ± 0.0034 at the Z pole, and vertexes are indeed present and interfere destructively the luminosity front it soon became clear that dedicated a common treatment of statistical correlations and sys- to vary with energy – the highlight of LEP’s QCD meas- with the t-channel diagram, suppressing the cross section

monitors would be needed to measure small-angle Bhabha tematic uncertainties, setting a precedent for future inter- urements. This so-called running of αs w as ver ified over and stopping it from diverging. scattering (e+e– → e+e–), which proceeds at a much higher experiment cooperation. Many tests of the SM were per- a large energy range, from the tau mass up to 206 GeV, The second key LEP2 electroweak measurement was of rate than Z production. The trick was to design a compact formed, including tests of lepton universality (figure 1b), yielding additional experimental confirmation of QCD’s t h e m a s s a n d t o t a l d e c a y w id t h o f t h e W b o s o n, w h ic h w e r e electromagnetic calorimeter with sufficient position res- adding to the tau lepton results already mentioned. Anal- core property of asymptotic freedom (figure 2a). determined by directly reconstructing the decay products of olution to define the geometric acceptance, and to compare yses also demonstrated that the couplings of leptons and Many other important QCD measurements were per- the two W bosons in the fully hadronic (W+W– → qqqq) and + – this to calculations of the Bhabha cross section. quarks are consistent with the SM predictions. formed, such as the gluon self-coupling, studies of dif- semi-leptonic (W W → qqℓνℓ) decay channels. The com- The final ingredient for LEP’s extraordinary precision The combined electroweak measurements were used to ferences between quark and gluon jets, verification of the bi n e d L E P W-m a s s m e a s u r e m e nt f r o m d i r e c t r e c o n s t r uc t io n was a detailed knowledge of the beam energy, which make stunning predictions of the top-quark and Higgs- r u n n i n g b -q u a r k m a s s, s t ud ie s o f h a d r o n i s at io n m o d e l s, d at a a lo n e i s 80.375 ± 0.025(stat) ± 0.02 2(s y s t) G eV, t h e l a r g e s t r e q u i r e d t h e fo u r e x p e r i m e nt s t o w or k c lo s e l y w it h a c c e l- boson masses, m a nd m . A f ter t he 1993 Z-p ole s c a n, t he m e a s u r e m e nt s o f B o s e–E i n s t e i n c or r e l at io n s a n d d e t a i le d contribution to the systematic uncertainties originating t H The combined erator experts. Curiously, the first energy calibration LEP experiments were able to produce a combined meas- studies of hadronic systems in two-photon scattering pro- from fragmentation and hadronisation uncertainties. The After only electroweak was performed in 1990 by circulating protons in the LEP urement of the Z width with a precision of 3 MeV in time c e s s e s. T h e f u l l s e t o f m e a s u r e m e nt s e s t a bl i s h e d Q C D a s a r e l at io n b e t w e e n t h e Z-p ole o b s e r v a ble s, m a n d m , provides three weeks t W measurements ring – the first protons to orbit in what would eventually for the 1994 winter conferences, allowing the prediction c o n s i s t e nt t h e or y t h at a c c u r at e l y d e s c r i b e s t h e p h e n o m- a stringent test of t he SM and constrains t he Higgs mass. of data taking were used b e c o m e t h e L HC t u n n e l, b ut at a m e a g r e e n e r g y o f 20 G eV. mt = 177 ± 13 ± 19 GeV where the first error is experimental enology of the strong interaction. and 10,000 to make The speed of the protons was inferred by comparing the and the second is due to mH not being known. A month Fol lo w i n g s uc c e s s f u l Z o p e r at io n s d u r i n g t h e “L E P 1” p h a s e To the Higgs and beyond Z decays, r a d io -f r e q ue n c y e le c t r ic fie ld n e e d e d t o k e e p pr o t o n s and later the CDF collaboration at the Tevatron announced the i n 1989–1995, a s e c o n d L E P e r a d e v o t e d t o a c c u r at e s t ud ie s Before LEP started, the mass of the Higgs boson was basi- stunning the number electrons circulating at 20 GeV on the same orbit, allow- p o s s i ble e x i s t e n c e o f a t o p q u a r k w it h a m a s s o f 176 ± 16 G eV. of W-boson pair production at centre-of-mass energies c a l l y u n k n o w n. I n t h e s i m ple s t v e r s io n o f t h e S M, i n v ol v i n g predictions of of neutrinos ing a measurement of the total magnetic bending field Both CDF and its companion experiment D0 reached 5σ above 160 GeV got under way. Away from the Z resonance, a single Higgs boson, the only robust constraints were its the top quark was found to on which the beam energy depends. This gave a 20 MeV “discovery” significance a year later. It is a measure of the electron-positron annihilation cross section decreases non-observation in nuclear decays (forbidding masses and Higgs be three u n c e r t a i nt y o n t h e Z m a s s. To r e d uc e t h i s t o 1.7 M eV for t h e t h e c o m ple x it y o f t h e Z-b o s o n a n a l y s e s (i n p a r t ic u l a r t h e s h a r pl y; a s s o o n a s t h e c e nt r e-o f-m a s s e n e r g y r e a c h e s t w ic e b e lo w 1 4 MeV) and the need to maintain a sensible, calcu- boson masses

34 CERN COURIER SEPTEMBER/OCTOBER 2019 CERN COURIER SEPTEMBER/OCTOBER 2019 35

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FEATURE LEP’S PHYSICS LEGACY ADVERTISING FEATURE

lable theory (ruling out masses above 1 TeV). In 1990, soon final LEP-wide combination excluded, at 95% confidence a f t e r t h e fi r s t L E P d at a-t a k i n g p e r io d, t h e f u l l H i g g s-b osn level, a SM Higgs boson w it h mass below 114.4 G eV. m a s s r a n g e b e lo w 2 4 G eV w a s e x c lud e d at 95% c o n fid e n c e The four LEP experiments carried out many other level by the LEP experiments. Above this mass the main searches for novel physics that set limits on the exist- Vacuum solutions: it’s good to talk d e c a y o f t h e H i g g s b o s o n, o c c u r r i n g 80% o f t h e t i m e, w a s ence of new particles. Notable cases are the searches for Like many big-science research facilities, the European predicted to be its decays into b quark–antiquark pairs, additional Higgs bosons in two-Higgs-doublet models and X-ray Free Electron Laser (European XFEL) has the followed by pairs of tau leptons, charm quarks or gluons, their minimal supersymmetric incarnation. Neutral scalar numbers to impress. The 1.2bn facility, which is while the WW* decay mode starts to contribute at the and pseudoscalar Higgs bosons lighter than the Z boson located in Hamburg, Germany, uses superconducting linear accelerator technology to generate 27,000 X-ray maximum reachable masses of approximately 115 GeV. The and charged Higgs bosons up to the kinematic limit of their flashes per second, with a pulse duration of less than main production process is Higgs-strahlung, whereby a p a i r pr o d uc t io n w e r e a l s o e x c lud e d. Sup e r s y m m e t r ic p a r- 100 fs and a brilliance that’s orders of magnitude Higgs is emitted by a virtual Z boson. t ic le s s u ffe r e d a s i m i l a r f at e, i n t h e t h e or e t ic a l l y at t r a ctive greater than any other conventional X-ray source. During the full lifetime of LEP, the four experiments assumption of R-parity conservation. The existence of That unique radiation is put to work in the European kept searching for neutral and charged Higgs bosons in s le p t o n s a n d c h a r g i n o s w a s e x c lud e d i n t h e l a r g e s t p a r t o f XFEL’s underground experimental hall, where six several models and exclusion limits continued to improve. t h e p a r a m e t e r s p a c e for m a s s e s b e lo w 70–100 G eV, n e a r t h e scientific instruments enable international teams of In its last year of data ta k ing, when t he cent re-of-mass kinematic limit for their pair production. Neutralinos with researchers and industrial users to carry out a diverse energy reached 209 GeV, ALEPH reported an excess of masses below approximately half the Z-boson mass were programme of basic and applied materials research – from mapping the atomic details of cells, viruses and four-jet events. It was consistent with a 114 GeV Higgs also excluded in a large part of the parameter space. The biomolecules to time-resolved investigations of boson and had a significance that varied as the data LEP exclusions for several of these electroweak-produced chemical reactions and structural imaging of Under pressure: the HED experimental station will be used to study matter under extreme conditions, were accumulated, pea k ing at an instantaneous sig ni f- s up e r s y m m e t r ic p a r t ic le s a r e s t i l l t h e m o s t s t r i n g e nt a n d nanoelectronic materials. It is very hard including new extreme-pressure phases, solid-density plasmas and phase transitions of complex solids in icance of around 3.9 standard deviations. The other three most model-independent limits ever obtained. high magnetic fields. (Courtesy: European XFEL/Jan Hosan) to remember Underpinning that collective endeavour and spanning e x p er i me nt s c a re f u l ly s c r ut i n i s e d t he i r d at a to con fi r m It is very hard to remember how little we knew before the 3.4 km long facility (XFEL accelerator, X-ray how little we or disprove ALEPH’s suggestion, but none observed any L E P a n d t h e g i a nt s t e p t h at L E P m a d e. It w a s o f t e n s a id t h at beamlines and the experimental hall) are all manner of objectives. The design review, tighter tolerances, On a day-to-day basis, what does the operational knew before lo n g-l a s t i n g e x c e s s i n t h at m a s s r e g io n. Fol lo w i n g m a n y LEP discovered electroweak radiative corrections at the enabling vacuum technologies, including chambers and cleaning, vacuum test and bake-out are all part of that end-stations, CF flange systems, feedthroughs, sample collaboration with KJLC. interaction look like? LEP and the d i s c u s s io n s, t h e L E P r u n w a s e x t e n d e d u nt i l 8 No v e m b e r level of 5σ, opening up a precision era in par ticle physics manipulators, valves, pumps and a range of associated It’s all about listening to the customer, giant step that 2000. However, it was decided not to keep running the t h at c o nt i nue s t o s e t t h e s t a n d a rd t o d a y a n d offe r g u id a n c e hardware and instrumentation. Connected customers understanding requirements and ongoing LEP made fol lo w i n g y e a r s o a s n o t t o i m p a c t t h e L HC s c h e d u le. T h e on t he elusive new physics beyond t he SM.  Luis Lopez is a systems integration engineer on another dialogue. For contracts involving bespoke Building the relationship European XFEL experiment, the Single Particles, vacuum parts, subsystems and chambers, we’ll The European XFEL’s High-Energy Density (HED) Clusters and Biomolecules and Serial Femtosecond review the customer’s sketches before talking to instrument is a case in point. Here the XFEL’s ultrashort Crystallography (SPB/SFX) instrument. SPB/SFX is them about what they’re trying to achieve. The X-ray laser pulses enable fundamental studies of primarily focused on 3D diffractive imaging and job then is to deliver as closely as possible matter at extremes of temperature and pressure – structural dynamics (on timescales of milliseconds to against the technical specifications, delivery time Services simulating conditions in the interiors of large planets – femtoseconds) of biological samples such as and price. It’s often an iterative process – that’s High-end test & measurement services and at extreme electric or magnetic field strengths. macromolecules, viruses, organelles and cells. what’s good about this working relationship. (Analog/Digital Signal Integrity, up to 20 GHz) Some technical features we may be able to “Scientists will use the HED instrument to investigate Although the scientific and vacuum system compromise and trade-off versus others where Hardware, fi rmware & software development what happens to a material when it’s compressed to requirements for SPB/SFX differ from the HED we might be able to do better than specification. Timing systems very high density and changes state from a solid to a experiment, the SPB/SFX experimental team clearly Are there other ways you look to reinforce the plasma,” says Ian Thorpe, instrument engineer for the values the same close working relationship with the manufacturer-customer relationship? Consulting & integration HED programme. KJLC manufacturing division. “We have a direct We recently organized a one-day workshop on Trainings (basic and advanced) connection with the product specialists and engineers,” fundamental aspects of vacuum science, Back in May, Thorpe and his colleagues initiated a says Lopez. “On custom-made parts, that interaction is technology and engineering for the staff at the series of in-house experiments with the HED instrument welcomed, with KJLC staff often coming up with European XFEL. This is something we’ve run Turn Key Systems – effectively a user-assisted commissioning programme alternative options, improvements and work-arounds previously at other European institutions, Low Level RF Controls to ensure that the set-up is fit for purpose ahead of full to our original designs.” helping to shape best practice in vacuum We speak go-live later in the summer. “The first of these GigE Vision image processing systems applications. It’s typically a diverse audience: experiments successfully characterized the focus,” early-career scientists and engineers as well as Industrial test automation & quality control explains Thorpe. “This is critical because we’re working staff with lots of experience. There was even on very small samples and you get the highest detail It’s all about relationships someone from purchasing and procurement at and pressure if you focus the X-ray and optical laser MicroTCA Training Dialogue, trust and, most important of all, the European XFEL event. Our technical director MicroTCA beams into a very tight spot.” Basic building blocks & components listening to your customer. Jonathon Ward, of education, J R Gaines, has years of experience product specialist at KJLC, tells Physics World in the field of vacuum science and engineering In terms of its vacuum specifications, the HED System assembly & confi guration about the vacuum vendor’s forward- looking and this type of forum enables us to share our instrument requires a mix of ultrahigh-vacuum and take on the manufacturer-customer technical capability, expertise and domain System management (incl. MCH and IPMI) high-vacuum technologies for the X-ray optics/ relationship. knowledge more widely. At the same time, we’re diagnostics enclosure and sample chamber. Many Come Communication protocols learning new things from our customers. It’s a standard catalogue parts are available via the (e.g. PCI Express, Gigabit Ethernet) What are your priorities when dealing with a big- two-way street. European XFEL’s online ordering system, with science customer like the European XFEL? Timing, triggers & interlocks Kurt J. Lesker Company (KJLC) among the We want to be the preferred partner for all things What are the commercial benefits of working with registered suppliers approved by the facility’s Support for development in MicroTCA vacuum – from a commercial, manufacturing and a high-profile customer like the European XFEL? procurement department. talk to us technology perspective. For me and my The European XFEL is at the leading edge of Troubleshooting procedures colleagues in the manufacturing division, the scientific endeavour. If you’re a trusted supplier However, it’s KJLC’s capabilities in the manufacture and task is to build relationships and trust with the for a customer like them, it opens doors with supply of custom vacuum parts, subsystems and scientists and engineers at the European XFEL – other big-science initiatives. chambers that sets the working relationship apart. Tel. +49 (0) 8998 1887 finding out what they’re working on right now None of the European XFEL’s demands are Registration & details: [email protected] but also what they’re going to need in three, straightforward, and the delivery of custom vacuum techlab.desy.de four, even five years’ time. They’re thinking techlab.desy.de/services/training orders relies on a robust feedback loop between about budgets on that timeframe now and that’s manufacturer and customer. where we want to position ourselves. Put another way: we’re not here for the short term, www.lesker.com In this way, product specialists and engineers at KJLC we’re here for the long term. review the customer’s designs to fully understand the • The European XFEL gets no commercial advantage European XFEL’s technical requirements and scientific from its participation in this article. 36 CERN COURIER SEPTEMBER/OCTOBER 2019

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FEATURE THE STORY OF LEP Got radiation? THE See what you’ve been missing GREATEST LEPTON COLLIDER

LEP was the highest energy e+e– collider ever built, with levels of precision that remain unsurpassed in accelerator physics. Former CERN director of accelerators Steve Myers Photo courtesy of EUROfusion. Website: www.euro-fusion.org Photo courtesy of EUROfusion. Website: www.euro-fusion.org tells LEP’s story from conception to Imaging in radiation environments just got easier its emotional final day.

With superior capabilities for operating in radiation environments, the MegaRAD cameras provide few minutes before midnight on a summer’s evening Collider (SLC) in California. But LEP was off to a fantastic Focus and bend excellent image quality well beyond dose limitations of conventional cameras, and are well suited in July 1989, 30 or so people were crammed into a start and its luminosity increase was much faster than at A quadrupole for radiation hardened imaging applications A back room at CERN’s Prévessin site in the French its relatively untested linear counterpart. A short arti- stands next to one of countryside. After years of painstaking design and con- cle capturing the transatlantic rivalry appeared in the the long dipole struction, we were charged with breathing life into the Economist on 19 August 1989. “The results from California magnets that largest particle accelerator ever built. The ring was com- are impressive,” the magazine reported, “especially as they curved electrons plete, the aperture finally clear and the positron beam made come from a new and unique type of machine. They may and positrons a f u l l t u r n o n o u r fi r s t at t e m p t. M i nut e s l at e r b e a m s w er provide a sure answer to the generation problem before around LEP’s circulating, and a month later the first Z boson event was L E P d o e s. T h i s e x pl a i n s t h e h a s t e w it h w h ic h t h e fi n i s h i n g 27 km-long ring. observed. Here began a remarkable journey that firmly touches have been applied to LEP. The 27 km-long device, established the still indefatigable Standard Model of par- six years in the making, was transformed from inert hard- ticle physics. ware to working machine in just four weeks – a prodigious So, what can go wrong when you’re operating 27 kilo- feat, unthinkable anywhere but at CERN. Even so, it was MegaRAD3 produce color MegaRAD1 produce KiloRAD PTZ radiation metres of particle accelerator, with ultra-relativistic still not as quick as Carlo Rubbia, CERN’s domineering or monochrome video up to monochrome video up to resistant camera with leptons whizzing around the ring 11,250 times a second? director-general might have liked.” 6 6 3 x 10 rads total dose 1 x 10 rads total dose Pan/Tilt/Zoom The list is long. The LEP ring was packed with magnets, power converters, a vacuum system, a control system, a Notes from the underground In the United States: International: cryogenics system, a cooling and ventilation system, beam LEP’s design dates from the late 1970s, the project being For customer service, call 1-800-888-8761 For customer service, call [01) 315-451-9410 instrumentation – and much more. Then there was the led by accelerator-theory group leader Eberhard Keil, RF control system, fibres, networks, routers, gateways, soft- group leader Wolfgang Schnell and C J “Kees” Zilverschoon. To fax an order, use 1-315-451-9421 To fax an order, use [01) 315-451-9410 THE AUTHOR ware, databases, separators, kickers, beam dump, radio- The first decision to be made was the circumference of Email: [email protected] Email: [email protected] frequency (RF) cavities, klystrons, high-voltage systems, the tunnel, with four options on the table: a 30 km ring Steve Myers executive chair of interlocks, synchronisation, timing, feedback… And, of that went deep into the Jura mountains, a 22 km ring that ADAM SA course, the experiments, the experimenters and every- avoided them entirely, and two variants with a length of Find out more at thermofisher.com/cidtec (Applications of body’s ability to get along in a high-pressure environment. 26.7 km that grazed the outskirts of the mountains. Then Detectors and LEP wasn’t the only game in town. There was fierce director-general Herwig Schopper decided on a circum- Accelerators to competition from the more innovative Stanford Linear ference of 26.7 km with an eye on a future proton collider Medicine), Geneva. For Research Use Only. Not for use in diagnostic procedures. © 2019 Thermo Fisher Scientific Inc. All rights reserved. All trademarks are the property of Thermo Fisher Scientific and its subsidiaries unless otherwise specified CERN COURIER SEPTEMBER/OCTOBER 2019 39

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FEATURE THE STORY OF LEP FEATURE THE STORY OF LEP CERN-GE-9902029-8 Just five months after the difficult excavation under Myers S CERN the Jura, one eighth of the accelerator (octant 8) had been Physics 93 Z 240 o completely installed, and, a few minutes before midnight Physics 94 Zo Physics 95 Z , 65–70 GeV on 12 July 1988, four bunches of positrons made the first o ) 200 Physics 96 80.5–86 GeV successful journey from the town of Meyrin in Switzerland –1 Physics 97 91–92 GeV (point 1) to the village of Sergy in France (point 2), a distance 160 Physics 98 94.5 GeV o f 2.5 k m. C r uc i a l l y, t h e “o c t a nt t e s t” r e v e a le d a s i g n i fic a nt Physics 99 96–102 GeV betatron coupling between the transverse planes: a thin Physics 00 100–104 GeV last value 120 –1 magnetised nickel layer inside the vacuum chambers was (14.06.00): 70.12 pb causing interference between the horizontal and verti- 80 cal focusing of the beams. The quadrupole magnets were integrated luminosity (pb a dju s t e d t o pr e v e nt a r e s o n a nt r e i n forc e m e nt o f t h e e ffe c t 40 each turn, and the nickel was eventually demagnetised. 0 Giving birth to LEP 1 15 29 43 57 71 85 99 113 127 141 155 169 183 197 The following months saw a huge effort to install equipment number of scheduled days (from start-up) in the remaining 24 km of the tunnel – magnets, vacuum chambers and RF cavities, as well as beam instrumentation, Fig. 2. Physicists pose in front of the final superconducting LEP1/LEP2 parameters Design Achieved Fig. 3. Top: Fig. 1. Blasting the for which it would be “decisive to have as large a tunnel injection equipment, electrostatic separators, electrical RF-cavity module to be installed. The modules gradually replaced LEP’s integrated LEP tunnel under as possible” (CERN Courier Ju l y/A u g u s t 2019 p39). T h e fi n a l cabling, water cooling, ventilation and all the rest. This their normal-conducting predecessors from 1994 to 1999, beam energy 55/95 GeV 46/98 GeV luminosity each day the Jura mountains design was approved on 30 October 1981 with Emilio Picasso was followed by conditioning the cavities, baking out and allowing the centre-of-mass energy to rise during LEP2. from 1993 to 2000. bunch current 0.75 mA 1.00 mA caused water to leading the project. Construction of the tunnel started in leak-testing the vacuum chambers, and individual test- Left: LEP surpassed burst into the 1983, after a standard public enquiry in France. ing. At the same time a great deal of effort to prepare the Unable to hone key parameters such as the tune and orbit total beam current 6.0 mA 8.4/6.2 mA every one of its key tunnel, forming an LEP’s tunnel, the longest-ever attempted prior to the software needed to operate the collider was made with corrections before beam was injected, we had two major design parameters. underground river Channel Tunnel, which links France and Britain, was carved limited resources. concerns: is the beam aperture clear of all obstacles, and vertical beam–beam 0.03 0.045/0.083 that took six months by three tunnel-boring machines. Disaster struck just two In the late 1980s, control systems for accelerators were are there any polarity errors in the connections of the parameter to eliminate. kilometres into the three-kilometre stretch of tunnel in going through a major transition to the PC. LEP was caught many thousand magnetic elements? So we nominated a emittance ratio 4.0% 0.4% the foothills of the Jura, where the rock had to be blasted up in the mess and there were many differences of opin- “Mr Polarity”, whose job was to check all polarities in because it was not suitable for boring. Water burst in and ion on how to design LEP’s control system. As July 1989 the ring. This may sound trivial, but with thousands of maximum luminosity 16/27 23/100 formed an underground river that took six months to elim- approached, the control system was not ready and a small connections it was a huge task. 1030 cm–2s–1 1030 cm–2s–1 inate (figure 1). By June 1987, however, part of the tunnel team was recruited to implement the bare minimum con- At a quarter to midnight on 14 July 1989, the aperture was IP beta function bx 1.75 m 1.25 m was complete and ready for the accelerator to be installed. trols required to inject beam and ramp up the energy. f r e e o f o b s t a c le s a n d t h e b e a m m a d e it s fi r s t t u r n o n o u r fi rst

attempt. Soon afterwards we managed to achieve a circu- IP beta function by 7.0 cm 4.0 cm Tidal forces, melting ice and the TGV to Paris l at i n g b e a m, a n d w e w e r e r e a d y t o fi n e t u n e t h e mu lt it ud e of parameters needed to prepare the beams for physics. 3 The goal for the first phase of LEP was electron– for the first time. The following 10 minutes seemed like 46475 11 November 1992 1999 LEP run 46498 16 August 1995 5 MeV positron collisions at a total energy of 91 GeV – the mass an eternity since none of the four experiments – ALEPH, 2 correlates with 46494 of the neutral carrier of the weak force, the Z boson. LEP DELPHI, L3 and OPAL – reported any events. I was in the lake level 46490 was to be a true Z factory, delivering millions of Zs for control room with Emilio Picasso and we were beginning 46470 1 46486 precision tests of the Standard Model. To mass-produce to doubt that the beams were actually colliding when Aldo tide prediction 46482 them required beams not only of high energy but also of Michelini called from OPAL with the long-awaited com- 0 high intensity, and delivering them required four steps. ment: “We h ave t he fi r st Z 0!” ALEPH and OPAL physicists 46465 46478 beam energy (MeV) beam energy (MeV) The first was to accumulate the highest possible beam had connected the Z signal to a bell that sounded on the heavy rainfall 46474 noisy period quiet period change in circumference (mm) –1 current at 20 GeV – the injection energy. This was a major arrival of the particle in their detectors. While OPAL’s bell 22:00 06:00 14:00 22:00 100 150 200 250 300 16:00 20:00 00:00 04:00 08:00 operation in itself, involving LEP’s purpose-built injection rang proudly, ALEPH’s was silent, leading to a barrage of daytime day daytime linac and electron–positron accumulator, the Proton Syn- complaints before it became apparent that they were wait- chrotron, the Super Proton Synchrotron (SPS) and, finally, ing for the collimators to close before turning on their sub LEP’s exquisite energy resolution meant that physicists had not only to account for tidal (left) and seasonal variations (middle), but also for noise caused by the departure of trains to Paris (right). (Plots by Jorg Wenninger.) transfer lines to inject electrons and positrons in opposite detectors. As the luminosity rose during the subsequent directions – these curved not only horizontally but also period of machine studies the bells became extremely LEP’s beam-energy resolution was so precise exception of a few hours in the middle of Experiment inconclusive! The real culprit, the v e r t ic a l l y a s L E P a n d t h e SP S w e r e at d i ffe r e nt h e i g ht s. T h e annoy ing and were sw itc hed off. that it was possible to observe distortion of the night when the signal was noise free. TGV (a high-speed train), was discovered by second step was to ramp up the accumulated current to the the 27 km ring by a single millimetre, Everybody had their own pet theory. I believed accident a few weeks later during a discussion energy of the Z resonance with minimal losses. Thirdly, From the Z pole to the WW threshold whether due to the tidal forces of the Sun it was some sort of effect coming from planes with a railway engineer: leakage currents on the beam had to be “squeezed” to improve the collision The first physics run began on 20 September 1989, with and Moon, or the seasonal distortion caused interacting with the electrical supply cables. the French rail track flowed through the LEP rate at the interaction regions by changing the focusing of L E P’s t o t a l e n e r g y t u n e d for fi v e d a y s t o t h e Z m a s s p e a kat by rain and meltwater from the nearby Some nights later I could be seen sitting in vacuum chamber with the return path via the quadrupoles on either side of the experiments, thereby 91 GeV, providing enough integrated luminosity to generate mountains filling up Lac Léman and weighing a car park on the Jura at 2 a.m., trying to the Versoix river back to Cornavin. The noise reducing the transverse cross section of the beam at the 1400 Zs in each experiment. A second period followed, this On 13 August down one side of the ring. In 1993 we noticed prove my theory with visual observations, hadn’t been evident when we first measured collision points. time with the energy scanned through the width of the Z 1989, the even more peculiar random variations on but it was very dark and all the planes had the beam energy as TGV workers had been on Fol lo w i n g t h e h i g h l y s uc c e s s f u l fi r s t t u r n o n 1 4 Ju l y 1989, at fiv e d i ffe r e nt b e a m e n e r g ie s: at t h e p e aknd±1 G eV a n d beams the energy signal during the day – with the stopped landing several hours beforehand. strike. we spent the next month preparing for the first physics ±2 G eV t o e it h e r s id e, a l lo w i n g t h e e x p e r i m e nt s t o m e a s u r e collided for run. Exactly a month later, on 13 August, the beams collided the width of the Z resonance. First physics results were the first time

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FEATURE THE STORY OF LEP FEATURE THE STORY OF LEP

The bizarre episode of the bottles in the beampipe bottles in the beampipe”). The aim, however, was clear: CERN-AC-0012011-01 i nj e c t a s muc h c u r r e nt a s p o s s i ble i nt o b o t h b e a m s, r a m p The story of the sabotage of LEP has the energy up to 45 GeV, squeeze the beam size down at

grown in the retelling, but I was there the collision points, collide and then spend a few hours CERN-HI-0011012 in June 1996, hurrying back early delivering events to the experiments. The reality was from a conference to help the machine hours of furious concentration, optimisation, and, in the operators, who had been struggling CERN-PHOTO-8301589-1 early days, fr ustrat ing disappointment. to circulate a beam for several days. In the early years, filling LEP was a delicate hour-long After exhausting other possibilities, process of parameter adjustment, tweaking and coaxing it became clear that there was an the beam into the machine. On a good day we would see obstruction in the vacuum pipe, and not a word. Someone got a long pole the beam wobble alarmingly on the UV telescopes, lose we detected the location using the to poke out the offending article – out a bit and watch the rest struggle up the ramp. On a bad beam position system. It appeared to it came, and my guess was correct: it day, futile attempt after futile attempt, most of the beam be around point 1 (where ATLAS now was a Heineken beer bottle, which had would disappear without warning in the first few sec- sits), so we opened the vacuum seal indeed refreshed the parts no other onds of the ramp. The process used to last minutes and and took a look inside the beampipe beer could reach, as the slogan ran. A there was nothing you could do. We would stand there, using mirrors and endoscopes. hasty search revealed a second bottle. w at c h i n g t h e l i fe t i m e b uc k a n d d i p, a n d t h e p a i n s t a k i n g l y Not seeing anything, I frustratedly Upon closer inspection it was clear injected beam would either slowly or quickly drift out squeezed my head between the that the control room operators had of the machine. The price of failure was a turn around vacuum flanges and peered down almost succeeded in making the and refill. Success brought the opportunity to chance the Fig. 4. Left: media look on as (from left to right) Paul Collier, Mike Lamont and Steve Myers lament LEP’s final moments before being decommissioned and inside the pipe. In the distance was beam circulate despite the obstacles: squeeze – an equally hazardous manoeuvre whereby the replaced by the LHC. Right: the dismantling process began on 13 December 2000. Daniel Regin made the first cut with a hydraulic nibbling machine. something resembling a green concave there was a scorch burn along the interaction-point focusing magnets were adjusted to lens. “This looks like the bottom of label, indicating that they had almost reduce the beam size – and then perhaps a physics fill, and a lot of concentration was required. The experiment Higgs boson. Arguments against included delays to the start a beer bottle,” I thought, restraining managed to steer the beam past the and a period of relative calm. At this stage the focus would teams did well not to ring and make too many demands of the LHC of up to three years. There was also concern that myself from uttering a word to anyone bottles. If there had only been one m o v e t o t h e e x p e r i m e nt a l p a r t ic le p h y s ic i s t s o n s h i f t at t h e at t h is st age – request s were occasiona l ly rebuffed w it h Fermilab’s Tevatron would beat the LHC to the discovery in the vicinity. I went to the opposite they may have succeeded. The Swiss fo u r e x p e r i m e nt s. E a c h h a d t h e i r o w n p a r t ic u l a r c ol le c t i v e a brusque response. of the Higgs, and mundane but practical arguments about open end of the vacuum section and police interviewed me concerning this character, and their own way of dealing with us. We verged the transfer of human resources to the LHC and the impact peered into the vacuum pipe again: a act of sabotage but the culprit was between being accommodating, belligerent, maverick, On the verge of a great discovery? on the materials budget, including electricity costs. The green circular disk this time, but again, never unmasked. dedicated, professional and very occasionally hopelessly LEP’s days were never fated to dwindle. Early on, CERN had impending closure of LEP, when many of us thought we a m at e u r – s o m e t i m e s a l l w it h i n t h e s p a n o f a s i n g le s h i f t, a plan to install the LHC in the same tunnel, in a bid to scan were about to discover the Higgs, was perceived like the announced on 13 October, just three months after the final depending on t he attendant pressures. e v e r h i g h e r e n e r g ie s a n d b e t h e fi r s t t o d i s c o v e r t h e H i gs death of a dear friend by most of the LEP-ers. After each of testing of the accelerator’s components (see feature on The experiment teams paraded their operational effi- boson. However, on 14 June 2000, LEP’s final year of sched- the public debates on the subject a group of us would meet LEP’s physics legac y, p32). ciency numbers – plus complaints or congratulations – at uled running, the ALEPH experiment reported a possible in some local pub, drink a few beers, curse the disbelievers LEP dwelt at the Z peak from 1989 to 1995, during which twice weekly scheduling meetings. Well run and disci- Higgs event during operations at a centre-of-mass energy and cry on each other’s shoulders. This was the only “civil t i me t he fou r e x p e r i me nt s e a c h o b s e r ve d approx i m at e ly plined, ALEPH almost always had the highest efficiency of 206.7 GeV. It was consistent with “Higgs-strahlung”, war” that I saw in my 43 years at CERN. 4.5 million Z decays. In 1995 a major upgrade dubbed fi g u r e s; t h e i r a p p e a r a n c e s at s c h e d u l i n g m e e t i n g s n early whereby a Z radiates a Higgs boson, which was expected to The CERN research board met again on 7 November and LEP2 saw the installation of 288 superconducting cavities always a simple statement of 97.8% or thereabouts. This dominate Higgs-boson production in e+e– collisions at LEP2 again there was deadlock, with the vote split eight votes to (fi g u r e 2), e n a bl i n g L E P t o s it at or n e a r t h e W W t hresold was livened in later years by the repeated appearance of energies. On 31 July and 21 August ALEPH reported second eight. The next day, then director-general Luciano Maiani o f 161 GeV for the following five years. The maximum beam their coordinator Bolek Pietrzyk, who congratulated us and third events corresponding to a putative reconstructed announced that LEP had closed for the last time. It was a energy reached was 104.4 GeV. There was also a contin- each time we stepped up in energy or luminosity with Higgs mass in the range 114–115 G eV. deeply unpopular decision, but history has shown it to be uous effort to increase the luminosity by increasing the a strong, Polish-accented, “Congratulations! You have LEP was scheduled to stop in mid-September with correct: the Higgs was discovered at the LHC 12 years later, nu m b e r o f b u n c h e s, r e d uc i n g t h e e m it t a n c e b y a dju s t i n g achieved the highest energy electron–positron collisions two weeks of reserve time granted to the LEP exper- with a mass of not 115 but 125 GeV. LEP’s closure allowed a t he foc usi ng, a nd squeezi ng t he bunc hes more t ig ht ly at in t he universe!”, which was always gratif ying. Equally iments to see if new Higgs-like events would appear. massive redeployment of skilled staff, and the experience the interaction points, with LEP’s performance ultimately professional, but more relaxed, was OPAL, which had a After the reserve weeks, ALEPH requested two months g a i n e d for t h e fi r s t t i m e i n r u n n i n g l a r g e a c c e le r at or s w ent limited by the nonlinear forces of the beam–beam inter- strong British and German contingent. These guys under- more running to double its integrated luminosity. One on to prove essential to the safe and efficient operation a c t io n – t h e p e r t u r b at io n s o f t h e b e a m s a s t h e y c r o s s t h e s t o o d hu m a n n at u r e. Q u it e s i m pl y, t h e y br i b e d u s. Ev e r y was granted, yielding a 50% increase in the accumulated of the LHC. opposing beam. LEP surpassed every one of its design time we passed a luminosity target or hit a new energy data, and ALEPH presented an update of their results on 10 When LEP was finally laid to rest we met one last time parameters (fig ure 3). record they’d turn up in the control room with champagne October: the signal excess had increased to 2.6σ. Things for a n offic i a l w a k e (fi g u r e 4). A f t e r t h e m a c h inewasd- or c r at e s o f G e r m a n b e e r. Nat u r a l l y w e’d d o a n y t h i n g for were really heating up, and on 16 October L3 announced a mantled, requiring the removal to the surface of around Life as a LEP accelerator physicist t hem, happily mov ing heaven and ear t h to resolve t heir missing-energy candidate. By now the accelerator team 30,000 tonnes of material, some of the magnets and RF Being an accelerator physicist at LEP took heart as well problems. L3 and DELPHI had their own quirks. DELPHI, was pushing LEP to its limits, to squeeze out every ounce units were shipped to other labs for use in new projects. a s br a i n s. T h e s i s y p h e a n d a i l y t a s k o f c o a x i n g t h e s e e m- for e x a m ple, r a n t h e i r d e t e c t or a s a “s t at e m a c h i n e”, w h o s e of physics data in the service of the experiments’ search Today, LEP’s concrete magnet casings can still be seen ingly temperamental machine to optimal performance status changed automatically based on signals from the for the elusive Higgs. At the LEP committee meeting on scattered around CERN as shielding units for antimatter even led us to develop an emotional attachment to it. accelerator control room. All well and good, but they 3 November, ALEPH presented new data that confirmed and fixed-target experiments, and even as road barriers. Being an Challenges were unpredictable, such as for the engineers depended on us to change the mode to “dump beam” at their excess once again – it had now grown to 2.9σ. A LEP was the highest energy e+e– collider ever built. Its accelerator dispatched on a fact-finding mission to ascertain the the end of a fill, something that was occasionally skipped, request to extend LEP running by one year was made to legacy was and is extremely important for present and This was the physicist at cause of an electrical short circuit, only to discover two leaving DELPHI’s subdetectors on and them ringing us the LEPC. There was gridlock, and no unanimous recom- future colliders. The quality and precision of the physics only civil war LEP took heart deer, “Romeo and Juliet”, locked in a lover’s embrace d e s p e r at e l y for a m o d e c h a n g e. B a ffle d DE L PHI s t ud e nt s mendation could be made. data remain unsurpassed in luminosity, energy and energy that I saw in as well as having bitten through a cable, or the discovery of sab- o n s h i f t wo u ld a s k w h at w a s g oi n g o n. F i l l i n g a n d r a m pi n g All of CERN was discussing the proposed running of LEP calibration. It is the reference for any future e+e--ring my 43 years at brains otage with beer bottles (see “The bizarre episode of the were demanding periods during the operational sequence in 2001 to get final evidence of a possible discovery of the collider design.  CERN

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I s t h e fi n a n c i n g o f h i g h- e n e r g y Seria and the of isolat ion inside t he reg ion. f u l l a nd se ve n a sso c i ate d memb er i n st i- p h y s ic s pr i m a r i l y a r e s p o n s i bi l it y o f g o v- founding memer Wess strongly believed that science is e r n m e nt s? A n d, i f s o, c a n B a l k a n c o u nt r i e s of SMP a powerful means to infl uence the devel- 450 individual members. There are also do it properly? POWERED BY opment of society. From 1999 to 2003, 13 p a r t n e r i n s t it ut i o n s w orl d w i d e. D u r i n g I f t h e a n s w e r s t o t h e fi r s t t h r e e q ue s- h i s i n it i a t i v e “W i s s e n s c h a f t l e r i n G l o b a l it s 15 y e a r s SE E N E T-M T P h a s u n d e r t a k e n: tions are “yes”, and to the last one “no”, Ve r a nt w or t u n g” ( W IG V ), w h i c h t r a n s l a t e s more than 18 projects, mostly concern- to “Scientists in Global Responsibility”, i n g m o bi l it y a n d t r a i n i n g; 30 c o n fe r e n c e s, a n d t h e r ol e o f t h e E u r o p e a n Un i o n (EU). Cryogen provided a platform to connect and sup- workshops and schools; more than 300 I n t h e s i x or s e v e n c o u nt r ie s i n t h e r e g io n port individual researchers, groups and that are not yet members of the EU (and Free Probe i n s t it ut io n s w it h a fo c u s o n for m e r Yu g o - fellowships; and more than 250 joint which have a very unclear perspective slavia. Much was achieved during this papers. Following initial support from a b o ut j oi n i n g ), w e n e e d t o w or k o ut h o w The World’s Most Advanced Stations s h or t t i m e, s u c h a s t h e g r a nt i n g o f s c h ol- CERN’s theory department, a formal to f und f undamenta l sc iences in a sim- arships in mathematics and theoretical collaboration agreement resulted in the ilar way that Poland, Czech Republic, Digital Pulse Processor physics, a revival of interrupted schools joint CERN–SEENET-MTP PhD Training or “older” EU countries do. At the same for high-rate Spectroscopy Program with at least 80 students taking Applications include of intranet at several Serbian institutions. part in the fi rst cycle from 2015 to 2018. f ut u r e r ol e s o f n o n-EU i n s t it ut io n s s u c h nano science, materials Funding, initially from Germany, pro- Vital support also came from the European a s C E R N a n d t h e IC T P. T h e r e c e nt a c c e s- and spintronics Physical Societ y and ICTP Trieste. sion of Serbia to CERN as a full member • Up to 8 channels <5 K - 675 K cryocooler- former Yugoslavia to establish contacts In total, the investment provided for state, and with Croatia and Slovenia in the of simultaneous based systems and cooperation with many excellent SEENET-MTP from international funds, process of joining, are promising signs Vibration isolated for researc hers from all around t he world. it s m e m b e r s, n a t i o n a l f u n d s a n d i n-k i n d tow ards closer European integ rat ion. processing It was natural to expand the WIGV ini- s up p or t a m o u nt s t o a l m o s t €1 m i l l i o n. It Networking is the most natural and sub-micron sample stability • Over 3 Mcps t i a t i v e t o br i d g e t h e g a p b e t w e e n s o ut h- is quite an achievement – if we consider promising au x iliar y mec hanism to pre- Up to 8 probes, DC to 67 GHz, plus fiber optics processed by e a s t e r n a n d t h e r e s t o f E u r o p e. C o u nt r ie s t h a t t h e r e s u l t s r e l y m o s t l y o n t h e e ff or t s serve and build local capacity in funda- Zoom optics with camera and monitor t o t h e e a s t a n d s o ut h o f Yu g o s l a v i a – s u c h and good will of many individuals – but mental physics in the region. The next s there each channel Horizontal, vertical or vector magnetic field a s B u l g a r i a, G r e e c e, R o m a n i a a n d T u r k e y it is still much less than an average “EU SEENET Scientifi c-Advisory Committee something – have a reasonably strong presence in project”. This raises important questions and its Council meeting will take place [email protected] options are available specifi c to h i g h- e n e r g y p h y s i c s. O n t h e o t h e r h a n d, about maintaining SEENET-MTP’s eff orts. at ICTP Trieste from 20 to 23 October. It Tel: +1-510-401-5760 Other configurations: LHe, LN , room temperature 2 sotheast they share some similar economic and SEENET-MTP has “thermalised” the w i l l b e t h e r i g ht pl a c e, i f n o t t h e l a s t p o s- www.xia.com and UHV systems s c i e nt i fi c pr o bl e m s, w it h m a n y r e s e a r c h system – the network has made people sibility, to transfer the initial ideas and Erope at Contact us today: g r o up s f a c i n g i n s u ffi c ie nt fi n a n c i n g, i s o - in the region interact. Yet today, we fi nd a c h i e v e d r e s u l t s t o a n EU-s up p or t e d pr o - [email protected] deseres lation and lacking critical mass. ourselves asking similar questions that its j e c t t o b ol s t e r b e s t pr a c t ic e i n t h e B a l k a n s. www.janis.com /CryogenFreeProbeStation.aspx special founders asked t hemselves 15 years ago. www.facebook.com /JanisResearch treatment UNESCO-sponsored Balkan Workshop Is t here somet hing specifi c to sout heast  www.seenet-mtp.info/bridges

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CCSepOct19_Viewpoint_v6.indd 45 29/08/2019 15:03 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM OPINION GAS DOSING VALVES for rough to extreme vacuum INTERVIEW

Grappling with dark energy

Astrophysicist Adam Riess, who led one of the teams that discovered the accelerating expansion of the universe 20 years ago, discusses intriguing discrepancies in the value of the Hubble constant. Johns Hopkins University Hopkins Johns Could you tell us a few words about quantum states in the universe the discovery that won you a share of produces an enormous number for the the 2011 Nobel Prize in Physics? expansion rate that is about 120 orders Back in the 1990s, the assumption of magnitude higher than observed. was that we live in a dense universe This rate is so high that it would have governed by baryonic and dark matter, ripped apart galaxies, stars, planets, but astronomers could only account for before any structure was formed. SWITZERLAND (HQ) USA JAPAN KOREA CHINA 30% of matter. We wanted to measure The accelerating expansion can be T +41 81 771 61 61 T +1 800 935 1446 T +81 45 44003 40 T +82 31 662 6856 T +86 21 5032 6658 the expected deceleration of the due to what we broadly refer to as dark [email protected] [email protected] [email protected] [email protected] [email protected] universe at larger scales, in the hope energy, but its source and its physics TAIWAN SINGAPORE GERMANY FRANCE UNITED KINGDOM that we would find evidence for some remain unknown. It is an ongoing T +886 3 516 90 88 T +65 62525121 T +49 351 501 93400 T +33 4 85 88 00 72 T +44 192 645 2753 kind of extra matter that theorists area of research. Today we are making [email protected] [email protected] [email protected] [email protected] [email protected] www.vatvalve.com predicted could be out there. So, from further supernovae observations 1994 we started a campaign to measure to measure even more precisely the the distances and redshifts of type-1a expansion rate, which will help us to supernovae explosions. The shift in understand the physics behind it. a supernova’s spectrum due to the expansion of space gives its redshift, By which other methods can and the relation between redshift we determine the source of the and distance is used to determine acceleration? the expansion rate of the universe. Dark pronouncements Adam Riess of Johns Hopkins Today there is a vast range of By comparing the expansion rates at University in the US. approaches, using both space and two different epochs of the universe, ground experiments. A lot of work we can estimate the expansion rate of astronomical process, but nothing is ongoing on identifying more the universe and how it changes over came out. Barring a series of unrelated supernovae and measuring their time. We made this comparison in 1998 mistakes, we were looking at a new distances and redshifts with higher Wideband Microwave Signal Generators and, to our surprise, we found that feature of the universe. precision. Other experiments are Standalone and programmable signal generators that fit instead of decreasing, the expansion There were other puzzles at that also looking to baryonic acoustic in your hand. Portable, affordable, reliable. rate was speeding up. A stronger time in cosmology that the idea of oscillations that would provide 50MHz to 30GHz Frequency Range Low Phase Noise confir mat ion came a f ter combining an accelerating universe could also a standard ruler for measuring 10Hz Frequency Step Size Ethernet Connection our measurements with those of the solve. The so-called “age crisis” (many cosmological distances in the SCPI Automation Friendly Ultra-Precision Reference High-z Supernova Search Team. stars looked older than the age of universe. There are proposals to use Intuitive PC Software Stepped Power Control Magnets for research The result could be interpreted if the the universe) was one of them. This weak gravitational lensing, which is USB Powered Vernier Power Control universe instead of decelerating is meant that either the stellar ages are extremely sensitive to the parameters Only $2499 and medicine speeding up its expansion. too high or that there is something describing dark energy as well as the wrong with the age of the universe shape and history of the universe. scanditronix-magnet.se What was the reaction from your and its expansion. This discrepancy Redshift space distortions due to the colleagues when you announced your could be resolved by accounting for an peculiar velocities of galaxies can also findings? accelerated expansion. A new feature tell us something. We may be able to That our result was wrong! There were lear n somet hing from t hese different Mixers With Integrated Wideband Programmable understandably different reactions What is driving the accelerated in the dark types of observations in a few years. Local Oscillators RF Step Attenuators but the fact that two independent expansion? sector of the The hope is to be able to measure the Up to 90dB of attenuation 6, 12, 18, 22, and 30GHz bands teams were measuring an accelerating One idea is that the cosmological universe equation-of-state of dark energy with a Exceptionally low insertion loss expansion rate, plus the independent constant, initially introduced by appears 1% precision, and its variation over time USB powered & controlled confirmation from measurements of Einstein so that general relativity Optional ethernet control increasingly with about 10% precision. This will the Cosmic Microwave Background could accommodate a static universe, offer a bet ter understanding of whet her Starting at $50900 Starting at $39500 necessary (CMB), made it clear that the universe is linked to the vacuum energy. Today dark energy is the cosmological is accelerating. We reviewed all we know that the vacuum energy can’t to explain constant or perhaps some form of ds instruments possible sources of errors including be the final answer because summing the present energy temporarily stored in a scalar s WWW.DSINSTRUMENTS.COM the presence of some yet unknown the contributions from the presumed tension field t hat could c hange over t ime.

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OPINION INTERVIEW CERNCOURIER COMSOL REPORTING ON INTERNATIONAL CONFERENCE HIGH-ENERGY PHYSICS Is this one of the topics that you are us to extrapolate the evolution from the 2019 CAMBRIDGE currently involved with? Big Bang to the present cosmos – period Yes, among other things. I am also of almost 14 billion years. The model is 2426 SEPTEMBER working on improving the precision of the based on certain assumptions: that space CHURCHILL COLLEGE measurements of the Hubble constant, in t he early universe w as flat; t hat t here Gain unique insights on Ho, which characterises the present are three neutrinos; that dark matter the latest research and project state and expansion rate of our universe. is very nonreactive; that dark energy is

developments in particle Refined measurements of H o could similar to t he cosmolog ical constant; and physics and related fields point to potential discrepancies in the that there is no more complex physics. So cosmological model. one or perhaps a combination of these can be wrong. Knowing the original content Explore the latest innovation and techniques in cerncourier.com What’s wrong with our current of the universe and the physics, we should determination of the Hubble constant? be able to measure how the universe was The problem is that even when we expanding in the past and what should be account for dark energy (factoring in any its present expansion rate. The fact that multiphysics simulation. uncertainties we are aware of) we get a there is a discrepancy means that we don’t discrepancy of about 9% when comparing have the right understanding. Join us at the COMSOL Conference 2019 where you’ll get a fi rsthand look at the predicted expansion rate based on We think that the phenomenon that how innovators in your fi eld are adopting multiphysics modelling and simulation CMB data using the standard “ΛCDM” we call inflat ion is similar to what we applications, learn new technical skills and gain inspiration for your next project. cosmological model with the present call dark energy, and it is possible that expansion. The uncertainty in this there was another expansion episode in measurement has now gone below 2%, the history of the universe just after the MINICOURSES | PANEL DISCUSSIONS | KEYNOTE TALKS | EXHIBITION leading to a sig nificance of more t han 5σ recombination period. Certain theories while future observations from the SH0ES predict a form of “early dark energy” programme would likely reduce it to 1.5%. becomes significant giving a boost to There is something more profound the universe that matches our current in the disagreement of these two observations. Another option is the measurements. One measures how fast presence of dark radiation: a term that Learn more and register today at comsol.com/conference/cambridge the universe is expanding today, while could account for a new type of neutrino the other is based on the physics of the or for another relativistic particle present early universe – taking into account a in the early history of the universe. The specific model – and measuring how presence of dark radiation would change fast it should have been expanding. If the estimate of the expansion rate before these values don’t agree, there is a very the recombination period and gives us strong likelihood that we are missing a way to address the current Hubble- something in our cosmological model that constant problem. Future measurements connects the two epochs in the history of could tell us if other predictions of this our universe. A new feature in the dark theory are correct or not. sector of the universe appears in my view increasingly necessary to explain the Does particle physics have a present tension. complementary role to play? Oh definitely. Bot h collider and

When did the seriousness of the H0 astrophysics experiments could discrepancy become clear? potentially reveal either the properties of It is hard to pinpoint a date, but it was dark matter or a new relativistic particle between the publication of first results or something new that could change the from Planck in 2013, which predicted cosmological calculations. There is an

the value of H0 based on precise CMB overlap concerning the contributions of measurements, and the publication of t hese fields in understanding t he early

our 2016 paper t hat confir med t he H0 universe, a lot of cross-talk and blurring of measurement. Since then, the tension the lines – and in my view, that’s healthy. has been growing. Various people were convinced along this way as new data What has it been like to win a Nobel prize came in, while there are people who are at the relatively early age of 42? still not convinced. This diversity of It has been a great honour. You can choose opinions is a healthy sign for science: whether you want to do science or not, we should take into account alternative as long as this choice is available. So viewpoints and continuously reassess certainly, the Nobel is not a curse. Our the evidence that we have without taking team is continually trying to refine the anything for granted. supernovae measurements, while this is a growing community. Hopefully, if you How can the Hubble discrepancy be come back in a couple of years, we will interpreted? have more answers to your questions. The standard cosmological model, which contains just six free parameters, allows Interview by Panos Charitos CERN.

48 CERN COURIER SEPTEMBER/OCTOBER 2019

CCSepOct19_Interview_v3.indd 48 29/08/2019 10:41 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM SUPERCON, Inc. OPINION Superconducting Wire and Cable REVIEWS Standard and Specialty designs are available to meet your most demanding superconductor requirements. SUPERCON, Inc. has been producing niobium-based superconducting wires and cables for half a century. We are the original SUPERCON – the world’s first commercial producer of niobium-alloy based wire and The cutting edge of cancer research cable for superconducting applications. repat/IBEC T X handful of concepts is formidable. How- Standard SC Wire Types Product Applications The Physics of Cancer ever, La Porta and Zapperi argue that a more abstract and unifying approach By Caterina A M La Porta and NbTi Wires Magnetic Resonance Imaging is now needed to gain a deeper under- Stefano Zapperi Nb3Sn —Bronze Nuclear Magnetic Resonance standing. They advocate studying cancer Nb3Sn —Internal Tin High Energy Physics Cambridge University Press as a complex system with the tools of CuNi resistive matrix wires SC Magnetic Energy Storage several disciplines, in particular sub- Cancer is a heterogeneous phenomenon fie ld s o f p h y s ic s s uc h a s bio m e c h a n ic s, Fine diameter SC Wires Medical Therapeutic Devices that is best viewed as a complex system soft-condensed-matter physics and Aluminum clad wire Superconducting Magnets and Coils of cells interacting in a changing statistical mechanics. Wire-in-Channel Crystal Growth Magnets micro-environment. Individual exper- The book is structured in 10 self- Innovative composite wires Scientific Projects iments may fail to capture this reality, c o nt a i n e d c h a p t e r s. T h e fi r s t t w o pr es- given spatially and temporally lim- ent essential notions of cell and cancer ited scales of observation, however, in biology. The subsequent chapters deal recent years, physicists have contributed with different features of cancer from “We deliver superconductivity!” insights into the interplay of phenom- an interdisciplinary perspective. A dis- ena at different scales: gene regulatory cussion on statistics and computational Contact us at [email protected] networks and communities of cells or models of cancer growth is followed by organisms are two examples of sys- a chapter exploring the generation of www.SUPERCON-WIRE.com tems whose properties emerge from vascular networks in its biological, the behaviour of individual components. hydrodynamical and statistical aspects. ad.indd 1 28/03/2012 09:43 Unfortunately, however, such research is Next comes a mathematical discussion u s u a l l y c o n fi n e d t o j o u r n a l s a n d s p e cial- of tumour growth by stem cells – the ised conferences, hindering the entry of to the original literature. Cancer physics active and self-differentiating cells interested physicists into the field. The The book begins by observing that Breast cancer cells thought to drive the growth of cancers. A publication of a new interdisciplinary the “hallmarks” of cancer are not only attached to a couple of chapters treat the biomechan- textbook is therefore most welcome. yet to be understood, but have increased surface rich in ics of cancer cells and their migration La Porta and Zapperi’s The Physics of in number. Published at the turn of the collagen. in the body, before La Porta and Zapperi Your partner for passive rf components Cancer, one of the few books devoted to millennium, Douglas Hanahan and Rob- turn to the dynamics of chromosomes t h i s subje c t, br i ngs 15 yea rs of e xc it i ng ert Weinberg’s seminal paper identified and the origin of the genetic mutations TRANSMISSION LINES, COAXIAL & WAVEGUIDE and important results in cancer research six: sustaining proliferative signalling; t h a t c a u s e c a n c e r. T h e fi n a l t w o c h a p t e rs • to a wide audience. The book approaches evading growth suppressors; enabling fo c u s o n h o w t o fi g ht t u m o u r s, f r o m t he the subject from the perspective of replicative immortality; activating perspectives of both the immune system PATCH PANELS & SPLITTERS Dense, physics, chemistry, mathematics and invasion and metastasis; inducing angi- and pharmacological agents. Bright, Fast • computer science. As a result of the vast- o g e n e s i s; a n d r e s i s t i n g c e l l d e a t h. Ju s t 1 1 La Porta and Zapperi’s book isn’t just CUSTOMISED RF COMPONENTS n e s s o f t h e s u bj e c t a n d t h e br e v it y o f t h e years later the same authors published light reading for curious physicists – Crystals for your book, the discussion can occasionally an updated review adding four more it can also serve to guide interested feel superficial, but the main concepts hallmarks: avoiding immune destruc- researchers into a rich interdiscipli- World-Class Research are introduced in a manner accessible to tion; promoting inflammation; genome nary area. p h y s ic i s t s. T h e a ut h or s fol l o w a l o g ic a l instability and mutation; and deregu- State-of-the-art scintillation and detection solutions thread within each argument, and fur- lating cellular energetics. The amount Guido D’Amico Stanford University and

Crystals: Grown to spec nish the reader with abundant references of research that has been distilled into a Università di Parma. Materials Index within short lead times Cs2LiYCl6(Ce) the beginning of the last century, with Arrays: Linear and 2D BGO Csl CERN and the Higgs Boson: There is, detail. It is rare that one comes across a the discovery of the electron, quantum monograph as good as this. from 5mm to 200mm Csl (Na) CaF2(Eu) Nal The Global Quest for the perhaps, mechanics and relativity, and which was Gillies draws attention to the many Detectors: Single units an excessively GLuGAG Csl (TI) Nal (TI) Building Blocks of Reality only completed in the first decades of interplays and dialectics that led to our and complete assemblies glossy the next. It is also a hunt throughout present understanding of the Higgs LYSO CdW04 ZnW04 By James Gillies (PMT, CCD, and SiPM) presentation which CERN’s science, technology and boson. First of all, he brings to light Icon Books of progress culture grew in importance. Gillies has the scientific issues associated with the CONTACT US TODAY: MEET US AT: produced a lively and enthusiastic text basic constituents of matter, and the [email protected] SCINT IEEE NSS & MIC James Gillies’ slim volume CERN and the that explores the historical, theoretical, forces and interactions that give rise +44 1843 231166 www.exirbroadcasting.com Booth 21 Booth 505 Higgs Boson conveys the sheer excitement experimental, technical and political to the Standard Model. Secondly, he hilger.dynasil.com Exir Broadcasting AB of the hunt for the eponymous parti- aspects of the search for the Higgs boson highlights the symbiotic relationship Industrigatan 17 - SE-242 31 Hörby - Sweden s cle. It is a hunt that had its origins at w it h o ut g oi n g i nt o o p pr e s s i v e s c ie nt i fic between theoretical and experimental Free shipping when you mention CERN19 +46 415 30 14 00 - [email protected]

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CCSepOct19_Reviews_v3.indd 51 29/08/2019 10:43 CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CERNCOURIER.COM CERNCOURIER.COM OPINION REVIEWS PEOPLE research, each leading the other in turn, immensely hard and difficult decisions A few more pictures might help the and taking the subject forward. Finally, that have to be made during such enor- text and fix the various contributors CAREERS he shows the inter-development of the mous endeavours. Doing science is great in readers’ minds, though clearly the accelerators, detectors and experimental f u n b ut a l s o v e r y d i ffic u l t – b ut t h e n w hat book, part of a series of short volumes by methods to which massive computing are challenges for? Icon Books called Hot Science, is format- power had eventually to be added. This A pertinent example in the Higgs- ted for brevity. I also found the posi- is all coloured by a liberal sprinkling of boson story not emphasised in the book tioning of the important material on anecdotes about the people that made it occurred in 2000. The Large Electron applications such as positron emission all possible. Positron collider (LEP) was due to be tomography and the world wide web to From SUSY to the boardroom Complementing this is the story of closed down to make way for the LHC, be unfortunate, situated as it is in the CERN, both as a laboratory and as an but late in the year LEP’s ALEPH detec- final chapter, entitled “What’s the use?” ProtonMail institution, traced over the past 60 years tor recorded evidence suggesting a Higgs Perhaps instead the book could have Beginning as a student or so, through to its current pre-eminent boson might be being observed at a ended on a more upbeat note by return- standing. Throughout the book the reader mass of 114–115 GeV – although, unfor- ing to the excitement of the science and discussion in the CERN learns just how important the people tunately, not seen by the other experi- technology, and the enthusiasm of the cafeteria five years ago, involved really are to the enterprise: ments (see p32). Exactly this situation people who were inspired to make the ProtonMail has become their sheer pleasure, their commitment had been envisaged when not one but discovery happen. through the inevitable ups and downs, four LEP experiments were approved in CERN and the Higgs Boson is a jolly the leading provider of and their ability to collaborate and com- the 1980s. After considerable discussion good read and recommended to every- secure e-mail and a pete in the best of ways. LEP’s closure went ahead, much to the one. Whilst far from the first book on A ripping yarn, then, which it might unhappiness and anger of a large group the Higgs boson, Gillies’ offering dis- challenger of online seem churlish to criticise. But then again, of scientists who believed they were on tinguishes itself with its concise history business models. that is the job of a reviewer. There is, per- the verge of a great discovery. This made and the insider perspective available to haps, an excessively glossy presentation for a very difficult environment at CERN him as CERN’s head of communications of progress, and the exposition contin- for a considerable time thereafter. We from 2003 to 2015: the denouement of Former particle physicist Andy Yen ues forward apace without conveying the now know the Higgs was found at the the hunt for the Higgs. has set himself a modest goal: to many downs of cutting-edge research: LHC w it h a mass of 125 GeV, vindicating transform the business model of the technical difficulties and the many the original decision of 2000. Roger Cashmore University of Oxford. the internet. In the summer of 2013, following the Snowden security Subatomic Desire R Carlin four-note sequences: an expression of leaks, he and some colleagues at quantum indeterminacy, according to CERN started to become concerned Audiovisual performance, CERN, Traube. Fabiani’s video projections add about the lack of data privacy and 21 June to the surreal atmosphere by transposing the growing inability for individu- the sequences into colours, with an als to control their own data on the animation of bullets referencing the internet. It prompted him, at the Swiss composer Alexandre Traube Russian World War II navy shells that time a PhD student from Harvard and the Genevan video-performer were used to build CMS’s hadronic University working on supersym- Silvia Fabiani have collaborated to calorimeter. metry searches in the ATLAS exper- Noble goals ProtonMail CEO Andy Yen (left) and CTO Bart Butler, photographed at the company’s head office in form music and dance troupe Les In concert with the audiovisual iment, and two others to invent Geneva in March, want internet users to be more aware of how their personal data is being used. Atomes Dansants, with the aims of using display, three performers sing about “ProtonMail” – an ultra-secure CMS data to explore the links between their love for the microcosm. Clad in e-mail system based on end-to- privacy, then the whole business couple of hundred CERN people had to grow, and that he had been science and art, and establishing a lab coat, Einstein wig and reversed end encryption. model collapses.” using it, so why not open it up to forced into a “tough and high-risk” dialogue between Eastern and Western baseball cap, Doc MC Carré (David The Courier met with Yen and Anyone can sign up for a Pro- the world and see what happens? decision between ProtonMail and culture. Premiering their show Subatomic Charles) raps formulas and boogies Bart Butler, ProtonMail’s chief tonMail account. Doing so gen- Within three days of launching the his academic career. Eventually Desire at CERN’s Globe of Science and around the stage. He is accompanied by t e c h n ol o g y o ffic e r a n d fe l l o w C ERN erates a pair of public and private website, 10,000 people had signed deciding to take the leap, Harvard Innovation on 21 June during Geneva’s Doc Lady Emmy, played by the soprano alumnus, at the company’s Geneva keys based on secure “RSA”-type up. It was surprising and exciting, granted him a period of absence, annual Fête de la Musique, they took the Marie-Najma Thomas, and Poète headquarters to find out how out a encryption implementations and says Yen, but also scary. “E-mail and Yen set about dealing with the act to the detector that served as their Atomique – the Persian singer Taghi discussion in CERN’s Restaurant 1 open-source cryptographic librar- has to work. A bank or something tens of thousands of users who were muse, performing in the hangar above Akhabari – who peppers the perfor- was transformed into a company ies. User data is encrypted using might close down their websites waiting to get onto the service. the CMS experiment. mance with mystical extracts from with more than 100 employees a key that ProtonMail does not for an hour of maintenance once In need of cash, the fledgling Muon tracks from W, Z and Higgs Sufi poets Rûmi and Attâr, and medi- serving more than 10 million users. have access to, which means the in a while, but you can’t do that software outfit decided to try events served as inspiration for Traube, eval German abbess Hildegard of “The business model of the company cannot decrypt or access with e-mail.” something unusual: crowd funding. who was advised by CMS physicist Bingen, each of whom explores themes internet today really isn’t com- a user’s messages (nor offer data ProtonMail’s CERN origins (the This approach broke new ground in Chiara Mariotti of INFN. He began of the natural world in their writings. patible with privacy,” explains recovery if a password is forgotten). name came from the fact that its Switzerland, and ProtonMail soon by associating segments of CMS’s The performers contend that the lyr- Yen. “It’s all about the relation- The challenge, says Yen, was not founders were working on the became a test case in tax law as to muon system to notes. Inspired by ics speak about desire as the fuel for ship between the provider and cus- so much in developing the under- Large Hadron Collider) meant that whether such payments should be the detectors’ arrangement as four everything at the micro- and macro- tomer. If you are a Gmail user then lying algorithms, but in applying the technology could first come considered revenue or donation (the nested dodecagons, he assigned a scale. Elaborate, contemporary and you are not Google’s customer, this level of security to an e-mail under the scrutiny of technically authorities eventually ruled on the note from the chromatic scale to rich in metaphors, this is an experience you are the product that Google service in a user-friendly way. minded people – “early adopters”, former). But the effort was a huge each of the 12 sides of the inner- Subatomic desire system to specific frequencies as well, that some will find abstruce, but others sells to its real customer, which is In 2014, Yen and ProtonMail’s who play a vital role in the lifecycle success, raising 0.5 million Swiss most layer, and the note a sonorous Les Atomes he linked two intermediate microtonal will love. advertisers. With ProtonMail, the other cofounders, Jason Stockman of new products. But what might Francs in a little over two months. perfect fourth above to the corre- Dansants were notes to the transverse momentum Subatomic desire will next be per- people who are paying us are also and Wei Sun, entered a competi- be acceptable to tech-minded “Venture capital (VC) was a mys- sponding segment in the outer layer. inspired by muon and rapidity of the tracks. At several for med in Neuc hâtel on 14 September. our users. If we were ever to betray tion at MIT to pitch the idea. They people is not necessarily what the tery to us,” says Yen. “We didn’t Developing an initial plan to link the tracks at the CMS moments during the performance the the trust of the user base, which is lost, but reasoned that they had broader users want, says Yen. He know anybody, we didn’t have a s intermediate two layers of the muon experiment. musicians improvise using the resulting Letizia Diamante CERN. paying us precisely for reasons of already built the thing and got a quickly realised that the company business plan, we were just a few

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PEOPLE CAREERS

people writing code. But, funnily – then we had to actually do what says Yen. “If I was to give advice to learning and you have to have the enough, the crowd sourcing, in we’d promised: build a team, hire someone in my position five years right people around you.” addition to the money itself, got a people, scale up the product, and ago, then there isn’t a lot I could say. It was around that time, in 2015, lot of attention and this attracted have some sort of company to run Starting a company is something when Butler, also a former ATLAS interest from VCs.” A few months things, with corporate identity, new for almost everybody who does experimentalist working on super- Libera Beam Loss later, ProtonMail had received accounting, tax compliance etc. it, and I don’t think physicists are at symmetry and one-time supervisor 2 million Swiss Francs in seed There wasn’t really a marketing a disadvantage compared to some- of Yen, joined ProtonMail. “A lot of Monitor System - Consists of: plastic scintillator-based beam loss funding. plan… it was more of a technical one who went to business school. that year was based around evolving detector and dedicated electronics “It is one thing to have an idea challenge to build the service,” All you have to do is work hard, keep the product, he says. “There was big - Sensitive to: X-rays, Gamma-rays, electrons, difference between what the prod- protons and neutrons uct originally was versus what it - Where to use: LINAC, transfer lines, storage rings, needed to be to scale up. It’s not a traditional company – 10-15% of the extraction lines s t a ff t o d a y i s C E R N s c i e nt i s t s. A lot - Main functions: ADC raw data, loss integration / PT2026 NMR Precision Teslameter of former physicists have developed averaging / counting over user-configurable time into really good software engineers, intervals but we’ve had to bring in properly - Interfaces: EPICS, Tango, TCP-IP, Web-Server Reach new heights trained software engineers to add and command-line the rigour that we need. At the end of the day, it’s easier to teach a in magnetic eld string theorist how to code than it is to teach advanced mathematics and measurement complex cryptographic concepts to someone who codes.” scan and try out for free! With the company, Proton Tech- The Metrolab PT2026 sets a new nologies, by then well established standard for precision magnetometers. – and Yen having found time to hot- foot it back to Harvard for one “very Leveraging 30 years of expertise building painful and ridiculous” month to Instrumentation Technologies, d.o.o. / Velika pot 22, SI-5250 Solkan, Slovenia / e: [email protected] / w: www.i-tech.si the world’s gold standard magnetometers, write up his PhD thesis – the next it takes magnetic  eld measurement to milestone came in 2016 when Pro- tonMail was actually launched. It new heights: measuring higher elds with was time to begin charging for better resolution. accounts, and to provide those who already had signed up with pre- mium paid-for services. It was the The PT2026 offers unprecedented  exibility ultimate test of the business model: Multiphysics simulation in the choice of parameters, interfacing would enough people be prepared to pay for secure e-mail to make Pro- aids in predicting laser and probe placement, as well as greatly tonMail a viable and even profitable improved tolerance of inhomogeneous business? The answer turned out to elds. And with Ethernet & USB interfaces be “yes”, says Yen. “2016 was make cavity stability. or break because eventually the and LabVIEW software, it  ts perfectly into funding was going to run out. We modern laboratory environments. discussed whether we should raise money to buy us more time. But we In the 1950s, three scientists engaged in a patent war over who

www.agence-arca.com - Photo: Scott Maxwell, Master le - Photo: Scott Maxwell, Master www.agence-arca.com decided just to work our asses off invented the laser. We’ve come a long way since then, but laser instead. We came very close but we design continues to be challenging work. In order for lasers started generating revenue just as to function properly, their cavity mirrors have to be aligned the VC cash ran out.” Since then, ProtonMail has con- perfectly. Even after lasing for a while, they can stop working due tinued to scale up its services, for to the thermal lensing effect. Simulation can help. instance introducing mobile apps, The COMSOL Multiphysics® software is used for simulating and its user base has grown to more than 10 million. “Our main com- designs, devices, and processes in all fields of engineering, petitors are the big players, Google manufacturing, and scientific research. See how you can apply it and Microsoft,” says Yen. “If you to laser stability analysis. look at what Google offers today, it’s actually really nice to use. So the Pantone 286 Pantone 032 comsol.blog/laser-stability longer vision is: can we offer what Google provides — services that Visualization of ray are secure, private and beneficial to trajectories and temperature Magnetic precision has a name www.metrolab.com society? There is a lot to build there, in a Ti:sapphire laser cavity. ProtonDrive, ProtonCalendar, for s example, and we are working to

54 CERN COURIER SEPTEMBER/OCTOBER 2019

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put together that whole ecosystem.” saying that when Google or Face- model are becoming more and more option online. I think this choice is A big part of the battle ahead is book began they went out to grab apparent. If you talk to consumers, really important for the world and IOP Expanding Physics getting people to understand what people’s data. It’s just the way the there is no choice in the market. It it’s why we do what we do.” Energy Density Functional Methods is happening with the internet and internet evolved: people like free was just e-mail that sold your data. Energy Density for Atomic Nuclei their data, says Butler. “Nobody is things. But the pitfalls of this So we want to provide that private Matthew Chalmers editor. Functional Methods for Atomic Nuclei Edited by

Edited by Nicolas Schunck Appointments and awards Nicolas Schunck Wikicommons Betterwik The fourth edition of the Guido Higgs boson and top quark. The In the past 20 years, energy density functional (EDF) approaches have become a powerful Altarelli Award, which recognises Julius Wess Award is endowed framework to study the structure and reactions of atomic nuclei. This book provides an updated exceptional achievements from with €10,000 and is granted presentation of non-relativistic and covariant energy functionals, single- and multi-reference young scientists in the field of annually to elementary particle methods, and techniques to describe small- and large-amplitude collective motion or nuclei at high deep inelastic scattering and and astroparticle physicists excitation energy. Detailed derivations, practical approaches, examples and figures are related subjects, was awarded for exceptional experimental used throughout the book to give a coherent narrative of topics that have hitherto rarely been during the DIS2019 workshop in or theoretical scientific covered together. Torino, Italy, on 8 April. Jonathan achievements. EDITOR’S Gaunt of CERN was recognised for PICK Nicolas Schunck is research scientist at Lawrence Livermore National Laboratory. His work is ICTP announces next director his pioneering contributions to Foundation Gruber Winners of 2019 Beamline for centred on the development and applications of computational methods for nuclear energy Atish Dabholkar, a theorist from the theory and phenomenology Schools competition density functional theory, with a particular focus on the development of a fundamental description India, has been appointed the of double and multiple parton Two teams of high-school of nuclear fission. next director of the International scattering. Josh Bendavid, also students, one from the Praedinius

Centre for Theoretical Physics O’Connor K Gymnasium in Groningen, (ICTP) in Trieste, Italy. Currently Netherlands (below), and one from head of ICTP’s high-energy, the West High School in Salt Lake To access this title visit iopscience.org/books. If you have an idea for a book you’d like to discuss please cosmology and astroparticle City, US, have won CERN’s 2019 e-mail [email protected]. physics section, Dabholkar Beamline for Schools competition. will take up his new position In October, the teams will travel to in November. He will succeed A Korzhimanov DESY in Germany to carry out their Fernando Quevedo, who has proposed experiments together led the centre since 2009. with scientists from CERN and Dabholkar’s research has focused DESY. The Netherlands team on string theory and quantum CERN, and a member of the CMS “Particle Peers” will compare the black holes, and his appointment collaboration, received the award properties of the particle showers ucle G: N ar an comes at a time of expansion for for his innovative contributions originating from electrons with ics d P ys ar h t ic ICTP. Over the past 10 years, the with original tools to Higgs those created from positrons, while P f le o Journal of Physics G P l centre has hired more researchers physics and proton parton the “DESY Chain” team from the h a

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40 s o J Nuclear and Particle Physics initiatives in quantitative life brother of the late Guido Altarelli, with the large-scale structure of of scintillators for more efficient years sciences, high-performance Massimo Altarelli, was present the universe”. particle detectors. Since Beamline S computing, renewable energies at the ceremony and handed the for Schools was launched in 2014, ince 1975 and quantum technology. In certificates to the two winners. Julius Wess Award 2018

addition, ICTP has increased its Sally Dawson of Brookhaven M Mug presence with the opening of 2019 Dirac Medal and Prize National Laboratory has been four partner institutes in Brazil, The International Centre for granted the 2018 Julius Wess China, Mexico and Rwanda. Theoretical Physics (ICTP) Award by the KIT Elementary “Directing ICTP is a once in a in Italy has awarded its 2019 Particle and Astroparticle Physics lifetime opportunity due to its Dirac Medal and Prize to three Center of Karlsruhe Institute of unique mission and its big impact physicists whose research has Technology. She is recognised in developing countries. I am glad made a profound impact on for her outstanding scientific New open access agreement with CERN that when I leave in November modern cosmology. Viatcheslav contributions to the theoretical the institute will be in very good Mukhanov (Ludwig Maximilian description and in-depth almost 10,000 students from hands,” says Quevedo. University of Munich), Alexei understanding of processes in 84 countries have participated. Journal of Physics G: Nuclear and Particle Physics is Starobinsky (Landau Institute hadron colliders, in particular her This year, 178 teams from 49 now fully compliant with the CERN publication policy, Guido Altarelli Award 2019 for Theoretical Physics) and work relating to the physics of the countries worldwide submitted Private collection Private BNL making it even easier to publish with us. Rashid Sunyaev (Max Planck a proposal for the sixth edition Institute for Astrophysics) share of the competition. Due to the the prize for “their outstanding current long shutdown of CERN’s Submit your next article and enjoy the quality and contributions to the physics of the accelerators for maintenance and service of our community-led journal. cosmic microwave background upgrade, there is currently no with experimentally tested beam at CERN, which has opened Image: inspired by a figure in the first issue published implications that have helped up opportunities to explore in 1975, in celebration of its 40th anniversary iopscience.org/jphysg D D Warner et al 1975 J. Phys. G: Nucl. Phys. 1 95 to transform cosmology into a partnerships with DESY and other precision scientific discipline by laboratories.

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Image: inspired by a figure in the first issue published in 1975, in celebration of its 40th anniversary D D Warner et al 1975 J. Phys. G: Nucl. Phys. 1 95 CERNCOURIER.COM CERNCOURIER.COM RECRUITMENT Accelerators Photon Science Particle Physics Accelerators| Photon Science| Particle Physics | | Deutsches Elektronen-Synchrotron A Research CentreDeutsches of the Helmholtz Elektronen-Synchrotron Association A Research Centre of the Helmholtz Association For advertising enquiries, contact CERN Courier recruitment/classified, IOP Publishing, Temple Circus, Temple Way, Bristol BS1 6HG, UK. Karlsruhe Institute of Technology (KIT) – The Research University Te l +4 4 (0)1 17 930 1 264 E-m a i l s a le s@c e r nc ou r ie r.c om. For our location in Hamburg we are seeking: in the Helmholtz Association creates and imparts knowledge for Please contact us for information about rates, colour options, publication dates and deadlines. the society and the environment. It is our goal to make significant contributions to mastering the global challenges of humankind in DESY-Fellowships the fields of energy, mobility, and information. For this, about PHOTOPHOTO 9,300 employees of KIT cooperate in a broad range of disciplines in experimental particle physics in research, academic education, and innovation. In Division V – Physics and Mathematics, the KIT Department of INJECTORINJECTOR• Physics, invites applications for a DESY,DESY Zeuthen location,• is seeking: Professorship (W3) DESY,DESY is one Zeuthen of the world’s location,leading research iscentres seeking: for photon PostdocPostdocscience, particle (f/m) (f/m) and astroparticle for for the the physics Photo Photo as well Injector Injectoras accelerator Test Test in Experimental Particle Physics Facilityphysics. More PITZ than 2400 in Zeuthenemployees work at our two locations at the Institute of Experimental Particle Physics (ETP) (successor FacilityHamburg and PITZZeuthen in in science, Zeuthen technology and administration. of Prof. Dr. Thomas Müller). We are looking for an outstanding scientist working in the area Particle physics and the investigation of the fundamental building of experimental particle physics. We are particularly interested in DESYblocks of nature and their interactions are at the core of the DESY DESY a scientist who pursues precision measurements and searches for DESYmission. is one The of the lab world’s is among leading the researchglobally centresleading forresearch photon science,institutions in physics beyond the Standard Model at high-energy particle DESY is one of the world’s leading research centres for photon science, particlethis field. and astroparticle We take significant physics as wellresponsibility as accelerator in internationally physics. leading accelerators and initiates new research directions at future inter- particle and astroparticle physics as well as accelerator physics. projects, e.g. at CERN and at KEK, and on our campus. We develop national large-scale facilities. The successful applicant is expected Thedetectors Photo Injector and technologies Test Facility PITZ relevant in Zeuthen for our (near experimental Berlin) develops activities, high to play an active role in coordinated research efforts at KIT. The Photo Injector Test Facility PITZ in Zeuthen (near Berlin) develops high brightnessand we electronengage sourcesin scientific for Free computing Electron Lasersand in the (FELs) development like FLASH of KIT provides an excellent environment for research in particle and brightness electron sources for Free Electron Lasers (FELs) like FLASH andfuture European accelerators XFEL. The for main particle focus physics. of the research program at PITZ is on astroparticle physics. The successful candidate will be part of a and European XFEL. The main focus of the research program at PITZ is on team of senior scientists who maintain and develop the research further improvement of pulsed high brightness photo injectors and on deve- further improvement of pulsed high brightness photo injectors and on deve- in particle physics at KIT. ETP has long-term involvements in the lopmentsThe position towards future high brightness CW electron sources. We also work Accelerate your career! lopments towards future high brightness CW electron sources. We also work large-scale projects CMS and Belle II. Your participation in, or on beamYou are driven invited plasma to take acceleration an active for role particle in one and or astroparticlemore of the physics.following support of, the evolution of these projects is expected. The infra- on beam driven plasma acceleration for particle and astroparticle physics. areas at Hamburg. structure at ETP currently includes a semiconductor laboratory, The• positionOur involvements at CERN (ATLAS, CMS) and at KEK (Belle II) workshops and computer clusters. Close ties exist with the Tier-1 TheWork position in one of the world-leading international groups of physicists and computing centre GridKa. Research at ETP is funded by the BMBF, Join CERN for a unique work experience at the cutting edge of technology, in a place like • • ExperimentalWork in one of activities the world-leading on-site (ALPS international II and groupsfuture on-site of physicists and the DFG and the Helmholtz Association. •engineers for the development of photo injectors experiments)engineers for the development of photo injectors nowhere else on earth. Perform numerical simulations to support the accelerator R&D program ETP is part of the KIT Centre Elementary Particle and Astroparticle • • PreparationsPerform numerical for future simulations particle to physics support experiments, the accelerator in R&D particular program Physics (KCETA, see www.kceta.kit.edu for further information). •at PITZ or to optimize subcomponents of the photo injector towards detectorat PITZ orand to optimizetechnology subcomponents development of the photo injector towards The rich research environment in KCETA includes further large- applications of high brightness electron beams for FELs and in plasma • Scientificapplications computing of high brightness electron beams for FELs and in plasma scale projects such as the Pierre Auger Observatory in Argentina, acceleration experiments the IceCube experiment at the South Pole and the KATRIN experi- CERN has diverse student, graduate and professional opportunities open for application. • Acceleratoracceleration development experiments Development of innovative concepts and techniques for the diagnostics ment at KIT. Close collaborations exist with strong theoretical • Development of innovative concepts and techniques for the diagnostics Requirements•of high-quality electron and laser beams physics groups working on (astro)particle phenomenology. The of high-quality electron and laser beams •Organization Ph.D. in physics of and completed participation within in the the shift last operation four years of PITZ for acce- Karlsruhe School of Elementary Particle and Astroparticle Physics: Apply now and take part! • Organization of and participation in the shift operation of PITZ for acce- Science and Technology (KSETA) provides access to an excellent ••lerator Interest R&D in particle physics lerator R&D pool of Ph.D. students. • Expertise relevant for at least one of the areas listed above The appointed professor will be part of the ETP board of directors Requirements https://careers.cern RequirementsDESY-Fellowships are awarded for a duration of 2 years with the and assume responsibilities in the academic self-administration. Excellent university degree in physics or engineering with PhD The candidate is required to teach at all levels of the undergradu- • possibilityExcellent of universityprolongation degree by one in physics additional or engineering year. with PhD •Extensive experience in beam dynamics simulations with space charge ate and graduate curriculum (eventually in German) and to • Extensive experience in beam dynamics simulations with space charge Futher•dominated informations beams as and well a as link in numericalto the submission methods system for your supervise bachelor, master and Ph.D. students. A Habilitation dominated beams as well as in numerical methods applicationVery deep knowledgeand the references of accelerator can physicsbe found and here: accelerator technology degree or equivalent scientific and teaching qualifications are • Very deep knowledge of accelerator physics and accelerator technology required. www.desy.de/FellowFH•Very good knowledge of English is required and knowledge of German • Very good knowledge of English is required and knowledge of German KIT is pursuing the strategic goal of substantially increasing gen- The Paul Scherrer Institute PSI is the largest research institute for natural and engineering sciences within Switzerland. •is of advantage Pleaseis of note advantage that it is the applicants responsibility that all material, der balance and diversity of its faculty. As an equal opportunity We perform cutting-edge research in the fields of matter and materials, energy and environment and human health. By including letter of references, reach DESY before the deadline for the employer, KIT explicitly encourages applications from women as performing fundamental and applied research, we work on sustainable solutions for major challenges facing society, science For further information please contact Dr. Mikhail Krasilnikov, +49-33762-7- Forapplication further information to be considered. please contact Dr. Mikhail Krasilnikov, +49-33762-7- well as from all others who will bring additional diversity to the and economy. PSI is committed to the training of future generations. Therefore about one quarter of our staff are post-docs, 7213 or [email protected]. 7213 or [email protected]. university’s research and teaching. KIT provides support for dual post-graduates or apprentices. Altogether PSI employs 2100 people. Salary and benefits are commensurate with those of public service career couples and families. Applicants with disabilities will be Theorganisations position is limited in Germany. to 3 years. Classification is based upon qualifications preferentially considered if suitably qualified. The terms of For use at the Swiss Light Source (SLS) and SwissFEL - two of the most advanced X-Ray radiation sources worldwide – the Photon Science Detector Group develops The position is limited to 3 years. Salaryand and assigned benefits duties. are commensurate Handicapped with persons those ofwill public be given service preferen organi-ce employment are listed in § 47 Landeshochschulgesetz (LHG) of one- and two-dimensional high speed X-Ray detectors with frame rates of several kHz. For the design of single photon counting and charge integrating readout chips Salary and benefits are commensurate with those of public service organi- sationsto other in Germany. equally Classificationqualified applicants. is based uponDESY qualifications operates flexible and assigned work the State of Baden-Württemberg. for hybrid strip and pixel detectors we are looking for a sations in Germany. Classification is based upon qualifications and assigned duties.schemes. Handicapped DESY personsis an equal will beopportunity, given preference affirmative to other action equally employer qua- Qualified candidates should submit before 30 September 2019 duties. Handicapped persons will be given preference to other equally qua- a curriculum vitae, list of publications, as well as research and Chip Designer (Detector Development Photon Science Division) lifiedand applicants. encourages DESY applications operates flexible from women. work schemes. Vacant DESY positions is an at equal lifiedDESY applicants. are in general DESY open operates to part-timework. flexible work schemes. During each DESY application is an equal teaching statements to: Dekanat der KIT-Fakultät für Physik, opportunity, affirmative action employer and encourages applications from Karlsruher Institut für Technologie (KIT), 76128 Karlsruhe, Your tasks opportunity,procedure DESY affirmative will assess action employer whether and the encouragespost can be applications filled with from women. Vacant positions at DESY are in general open to part-time-work. Du- Germany, preferably by email to [email protected]. For • women. Vacant positions at DESY are in general open to part-time-work. Du- Work on chip design for XFEL- and Synchrotron detectors in collaboration with other chip designer in the Group and with the responsibility for a readout chip ringpart-time each application employees. procedure DESY will assess whether the post can be further information about this position please contact Prof. Dr. • Design and test of small prototypes and full scale chips ring each application procedure DESY will assess whether the post can be filledWe with are part-time looking employees.forward to your application via our application system: Margarete Mühlleitner, email: [email protected], • Collaborate in the system integration of the readout chips filled with part-time employees. or Prof. Dr. Günter Quast, email: [email protected]. www.desy.de/onlineapplication Your profile We are looking forward to your application quoting the reference code pre- KIT – The Research University in the Helmholtz Association We are looking forward to your application quoting the reference code pre- The successful candidate should have a degree in electronics, physics or related fields with experience in chip design. Experience in analogue chip design for hybrid ferablyDeutsches via our electronic Elektronen-Synchrotron application System: DESY Online-Application ferably via our electronic application System: Online-Application pixel detectors would be appreciated. You will work as a teamplayer in a stimulating international environment, giving you excellent opportunities for new initiatives. DeutschesHuman Resources Elektronen-Synchrotron Department | DESYCode: FHFE003/2019 Deutsches Elektronen-Synchrotron DESY We offer HumanNotkestraße Resources 85 Department | 22607 HamburgCode: MPO003/2017Germany Human Resources Department| Code: MPO003/2017 Our institution is based on an interdisciplinary, innovative and dynamic collaboration. You will profit from a systematic training on the job, in addition to personal NotkestraßePhone: +49 85 4022607 8998-3392 Hamburg |Germany Phone: +49 40 8998-3392 Notkestraße 85| 22607 Hamburg| Germany| Phone: +49 40 8998-3392 development possibilities and our pronounced vocational training culture. If you wish to optimally combine work and family life or other personal interests, we are able Deadlinehttp://www.desy.de/career for applications:| 31 January| 2018 | to support you with our modern employment conditions and the on-site infrastructure. Deadline for applications: 31 January 2018 www.desy.deDeadline for applications: 2019/09/30 Paul Scherrer Institut, Human Resources Management, Nicole Schubert, Forschungsstrasse 111, 5232 Villigen, PSI, Switzerland. www.psi.ch. www.desy.de For further information please contact Dr Bernd Schmitt, phone +41 56 310 23 14. Please submit your application online by 31 October 2019 for the position as a Chip Designer (index no. 6114-01).

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ELI Beamlines research centre in Dolní Břežany is part of Required skills: university degree in Computer Science, pan-European infrastructure ELI (Extreme Light Infrastructure) Engineering, Science, or related field • experience with working representing a unique tool of support of scientific excellence in with scientific data and metadata • experience with setting up Europe by making available its capacities to the best scientific and managing databases • experience with development of APIs • teams across the world. The aim of ELI Beamlines is to establish experience with programming in Python • good knowledge of Linux/ the most intensive laser system in the world and to operate it Unix programming environment • proficiency in English on a long-term basis. Due to ultra-high performances of 10 PW Desired skills: experience with machine learning for big data (1 petawatt = 1,000,000,000,000,000 watts) and concentrated processing • experience with control systems like TANGO intensities of up to 1024 W/cm2, we can offer our users a unique • experience in European projects and international collaborations edition source of radiation and beams of accelerated particles. The 2020 We offer: the opportunity to participate in this unique scientific Course 1 so called beamlines will enable groundbraking research in the area of physics and science dealing with materials, but also in project • competitive and motivating salary • flexible working hours TWO COURSES 20 January - 14 February • nice working environment • career growth • lunch vouchers, on Particle & Course 2 biomedicine and laboratory astrophysics and many other fields. ELI Beamlines is part of the Institute of Physics of the Czech pension contribution and 5 sick days • support of leisure time Astroparticle Detectors 17 February - 13 March Academy of Sciences, and it was open in 2015. activities by apply now The Institute of Physics of the Czech Academy of Sciences is a www.esipap.eu Discover what’s out there. holder of the HR Excellence in Research Award. It is awarded by Applications, containing CV, cover letter, contacts of references, [email protected] the European Commission to institutions which put significant and any other material the candidate considers relevant, should effort into improving their HR strategy and ensuring professional be sent to Mrs. Jana Ženíšková, HR specialist (jana.zeniskova@ Applications are welcome for Master students, and ethical working conditions. eli-beams.eu, +420 - 601560322). PhD students and junior professionals. careers Career opportunities for those with a background Information regarding the personal data processing and access Depending on their academic records, BSc students may in physics and related subjects to the personal data at the Institute of Physics of the Czech also be admitted. Academy of Sciences can be found on: https://www.fzu.cz/en/ Short participation available for Professionals ! ScientificA bumper-sized book Data with helpful Management careers advice, real-life Specialist case studies, as well processing-of-personal-data (Softwareas an extensive Engineer) employer directory powered by brightrecruits Job description:Download Your themain free mission Physics World will beapp totoday! implement solutions for cataloging experimental data and metadata and integrating them into PaNOSC and EOSC. You will collaborate with multiple teams at ELI as well as within PaNOSC project to bring data from their acquisitionRead online to publicly at physicsworld.com/careers accessible web services based on FAIR Data Principles (Findable, Accessible, Interoperable, Reusable).

DATA SCIENTIST / SOFTWARE DEVELOPER EXCITING CAREERS FOR STEM GRADUATES AND POSTGRADUATES

Tessella is a data science, analytics and software consultancy that works with global companies at the forefront of science and technology. We are leaders in the field of data science and analytics, helping clients solve their most complex technical challenges by unlocking the power of their data, enabling them to make better-informed business decisions. careers Our projects are varied and typically at the cutting-edge of high-tech R&D, for example: » Solving computational problems for chemists in drug discovery and development. Career opportunities for those with a » Modelling and simulating new products for FMCG clients and analysing data to improve processes. » Writing algorithms and solving complex mathematical problems to control satellites and radar systems. background in physics and related subjects » Solving the computational challenges of oil and gas exploration and production, from reservoir modelling to writing control systems. A bumper-sized book with helpful careers advice, We are looking for science, mathematics and engineering graduates and postgraduates to join us. Supported by our extensive training package, you will apply your deep domain knowledge and use a range real-life case studies, as well as an extensive of skills to create and develop innovative solutions that truly make a difference in the world. employer directory powered by brightrecruits

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Notes and observations from the high-energy physics community Accelerators get personal From the archive: October 1976 People and people … LEGO® bricks, pop-up books, cakes – all have all been turned into The 1970s saw abiding achievements in areas other than emerging model accelerators or detectors in the name of particle-physics new physics. outreach. But a father-and-daughter team from Sydney has taken the idea to a new level. Their Personal Particle Accelerator is a working At Fermilab, commissioning

model that uses computer-controlled electromagnets to power a of the Cancer Therapy Facility Fermilab steel ball around a t ransparent t ube. It star ted li fe five years ago CTF made smooth and steady when 12-year old Jo Collins was looking for a school project. After progress. Alan Jones, a CTF several years spent refining and improving the design with her father technician, is seen (right) and others, it’s now a kit that can be built at home or school, albeit positioning his head at the one that requires “a bit of technical experience with electronics neutron beam port during and technology”. Numerous experiments can be carried out with development. The first the open-source apparatus, such as testing the effects of gravity therapeutic irradiation took or friction, and a crowdfunding campaign recently launched on place in September, when a Kickstarter has raised more than AU$25,000 in pre-orders. This will volunteer patient, a woman enable upgrades such as evacuated tubes and options to change the When Compromise is Not an Option. NEW! suffer ing from cancer of t he direction of the ball, as in a real accelerator. For those keen to push the ADQ8-8C tongue, received a dose of boundaries of their wiring and soldering skills, the device even comes SLAC 8 CHANNELS, in a super-sized version. But what of the linear option? neutrons. She spent about High-Performance Digitizers for an hour at the facility, 10-BIT, 1 GSPS returning several times for further doses. Big Physics Applications Meanwhile, Soviet scientists attending a Digitizers from Teledyne SP Devices utilize patented conference on US-USSR calibration technology, the latest data converters, and cooperation in science, visited several American laboratories state-of-the-art FPGAs in order to achieve an unrivaled including Berkeley, Stanford, combination of high resolution and sampling rate. Their Fermilab and Brookhaven. They are seen above with their hosts versatility makes them ideal for applications such as CT scanners that don’t require during their visit to SLAC. Left to right: back row: Media corner travelers to separate liquids and O M Rodzianko (US translator), V A Yarba, V Matveev, J S Coleman beam position monitoring, plasma diagnostics, and gels in their hand luggage. (ERDA), Keller (SLAC); front row: D F Khokhlova, P A Cherenkov, “Before exploring higher energies, more. W K H Panofsky (SLAC), I V Chuvilo (Head of Delegation), it makes sense to me to build a V A Vasilyev, A Ts Amatuni, V F Kuleshov. muon collider, and to clarify the “We’re going to turn the UK into  Compiled from text on p353 and p355 of CERN Courier October 1976. question of the Higgs first. Here a kind of supercharged magnet, Supported features include: drawing scientists like iron filings we already have a particle that we Compiler’s note from around the world coming to • Up to 10 GSPS sampling rate with 14 bits resolution want to explore.” In the 1970s, nuclear medicine was in its infancy and help push forward projects like Carlo Rubbia calls for courage in east–west geopolitical tension was at its height. Half a • Open FPGA for custom real-time signal processing this.” deciding the next major collider, century later, cancer patients are being treated with UK prime minister Boris Johnson • Multiple form factors including MTCA.4, PXIe and PCIe in an interview with Quanta carbon ions in advanced hadron-therapy centres (see quoted on BBC News (8 August), magazine (7 August). p10). But the existential challenges we face need following a visit to the Culham • Multi-channel synchronization capabilities concerted efforts on many fronts – and most of all, Centre for Fusion Energy. “What was not so widely reported, peace. The successful collaborative approach taken by • White Rabbit synchronization (MTCA.4 only) however, is that streamlined the particle-physics community to achieve its goals, imaging of luggage and containers “Scientists are not fools. They know testifies to the benefits, often unforeseen, that accrue from global • Peer-to-peer streaming to GPU (PCIe only) has been achieved, in part, by that turmoil is inevitable for many cooperation. • Application-specific firmware speed up development improvements to the accelerators years.” that provide the electron beams for Andre Geim of the University of Cost to develop the estimated the scanners.” Manchester, who shared the 2010 Carsten Welsch of the University Nobel Prize in Physics for the 50 million lines of high-energy of Liverpool addressing “What discovery of graphene, quoted in >€0.5 physics code that have been have particle accelerators ever The Times (9 August) following the written, were they outsourced done for us?” in Physics World (20 UK government’s announcement billion August), following Heathrow of fast-track visa applications for to IT professionals rather than airport’s installation of new scientists. graduate students and postdocs. Learn more on our website www.spdevices.com

62 CERN COURIER SEPTEMBER/OCTOBER 2019

CERNCOURIER www. V o l u m e 5 9 N u m b e r 5 S e p t e m b e r / O c t o b e r 2 0 1 9 CAEN Electronic Instrumentation

NEW SCI-Compiler User Firmware Generator and Compiler for CAEN Programmable Boards

CAEN • Block diagram based user firmware generator and compiler • Automatic VHDL generation starting from logic blocks and virtual instruments • Automatic generation of drivers, libraries and demo software for Windows, Linux and macOS to implement communication between devices and PC software through USB, ethernet and VME protocol.

What is SCI-Compiler We introduce an innovative method to simplify the firmware development. DT5550W 128 Channel SiPM Readout System This method is based on a graphical programming interface consisting of blocks specifically developed for nuclear physics applications. The SCI-Compiler software allows to develop both purely digital applications, exploiting blocks like scaler, counter, pattern matching, logic analyzer and state machine, and analog processing applications, such as custom multichannel analyzer using charge integration, trapezoidal filter, spectrum and oscilloscope blocks. In addition, the SCI-Compiler software provides the function to read and test the ASICs, enabling the user to develop a sequencer for the ASIC control. er suppo CI-Compil rted boar S ds

Multichannel Analog Programmable Logic Unit 128 Channel DAQ System 32 Channel DAQ System

Front-End for SiPM

October_OFC.indd 1 28/08/19 16:50

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