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CERNJanuary/February 2020 cerncourier.com COURIERReporting on international high-energy WLCOMEE CERN Courier – digital edition Welcome to the digital edition of the January/February 2020 issue of CERN Courier.

On the cover of this issue, NASA Drew Morgan is photographed AMS 400 km above Earth’s surface installing a new coolant system for the Alpha Magnetic Spectrometer (AMS) during a crucial spacewalk on 2 December. KEEPS Masterminded by charm– co-discoverer Sam Ting of MIT, and assembled and overseen by an international team at CERN, AMS has been attached to the International Station since 2011. Its various ITS subdetectors, which include a silicon tracker embedded in a 0.15 T , have so far clocked up almost 150 billion charged cosmic rays with energies COOL up to the multi-TeV range and produced results that contradict conventional understanding. The new coolant system (which was delivered by an Antares rocket on 2 November) will extend the lifetime of AMS until the end of the decade, allowing more conclusive statements to be made about the origin of the unexpected observations. A full report on the unprecedented AMS intervention – and a taste of the experiment’s latest results – will appear on cerncourier.com following the final by Drew and his colleagues in mid-January.

Meanwhile, in this issue we investigate an intriguing anomaly in nuclear decay rates seen by the “Atomki” experiment, learn about the wider value of anomalies to phenomenologists, talk to theorist John Ellis about the past, present and future of the , and explore high-level attempts to solve the flavour puzzle. KATRIN’s quest for the mass, outreach for visually impaired audiences, the latest results from the LHC experiments and careers in are among other highlights of this first issue of the 2020s.

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EDITOR: MATTHEW CHALMERS, CERN   Voyage to the neutrino mass DIGITAL EDITION CREATED BY IOP PUBLISHING Atomki anomaly rekindled Tackling the flavour puzzle

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IN THIS ISSUE V o l u m e 60 N u m b e r 1 J a N u a r y /F e b r u a r y 2 02 0 It’s Time for a New Generation of Power ! MAGIC Ordan/CERN-PHOTO-201907-192-1 J Inc./ Entertainment Bros. DNEG/Warner

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CT-BOX Epic burst The MAGIC telescope detected Paradigm shift? John Ellis reflects on Gargantua The visual effects forInterstellar were the All-In-One Measurement and Calibration System of unrivalled energy. 10 the future of the field. 39 fruit of a collaboration with Kip Thorne. 45 Up to ±1.000 A, 1 ppm/K TC, 100 ksps Data-Logger and Oscilloscope 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 OBITUARIES Atomki anomaly Crystal calorimeter hones Twistors and loops Luigi Radicati 1919–2019 Full-Bipolar operation, Digital Control Loop, Ethernet Connectivity • Generating Device supported by Visual Easy-Driver software rekindled • BASE tests Higgs mass • LHCb on • PS turns 60 • Space– gargantuan effects • Jean-Pierre Blaser ’s dark the Vcb puzzle • More time symmetries Oliver James of DNEG 1923–2019 side • Physics tops plasma quenching in • APPEC, ECFA and discusses trends in the • B V Sreekantan FAST-PS-M finance • LHC schedule wide jets •Extreme NuPECC join • fast-growing visual- 1925–2019. 51 Digital Monopolar Power Supplies - up to 100 A updated • Epic gamma- electromagnetic Higgs Couplings effects industry. 45 High-Precision Monopolar Power Converters with Gigabit Ethernet burst. 7 fields. 15 workshop. 19 Embedded Linux OS, device supported by Visual PS software FeaTureS KATRIN FAST-PS Collider Tactile Digital Bipolar Power Supplies - up to ±30 A and ±80 V FLAVOUR PHYSICS KATRIN EXPERIMENT OUTREACH Full-Bipolar, Digital Control Loop, High-Bandwidth, 10/100/1000 Ethernet Who ordered all A voyage to the Engaging with Embedded Linux OS, device supported by Visual PS software of that? heart of the neutrino the invisible Recent work suggests KATRIN has begun The Tactile Collider that the flavour scale its seven-year-long project is helping FAST-PS-1K5 could be at a much lower programme to determine engagement with visually Digital Bipolar Power Supplies - up to ±100 A and ±100 V energy than previously the mass of the impaired and other 1.500 W, Paralleling via SFP/SFP+, 1 ppm/K TC, 10/100/1000 Ethernet thought. 23 antineutrino. 28 important audiences. 33 Embedded Linux OS, device supported by Visual PS software

NGPS oPINIoN DeParTmeNTS High-Stability 10-kW Power Supply - 200 A / 50 V VIEWPOINT INTERVIEW REVIEWS FROM THE EDITOR 5

Digital Control Loop, Paralleling via SFP/SFP+, 10/100/1000 Ethernet NASA Embedded Linux OS, device supported by Visual PS software Learning to love The Higgs, Ins and outs of NEWS DIGEST 13 anomalies collider calorimetry LETTERS 42 Ben Allanach says and all that Calorimetry for • APPOINTMENTS 46 the 2020s will sort John Ellis on Collider Physics & AWARDS current anomalies in supersymmetry in light • A history of ATLAS On the cover: Drew Morgan fundamental physics. 37 of the LHC. 39 • Maxwell’s Enduring performing maintenance RECRUITMENT 48 Legacy. 43 on the Alpha Magnetic BACKGROUND 54 Spectrometer in 2019. 5

www.caenels.com CERN COURIER JANUARY/FEBRUARY 2020 3

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Best Cyclotron Systems provides 15/20/25/30/35/70 MeV EDITOR Cyclotrons as well as 35 & 70 MeV Multi- (Alpha, Deuteron & Proton) Cyclotrons Currents from 100uA to 1000uA (or higher) depending on the particle beam are available on all BCS cyclotrons Extending the life of a unique experiment

Best 20u to 25 and 30u to 35 are fully upgradeable on site NASA t’s not often that CERN Courier has the opportunity to fea- ture an astronaut on its cover, but events unfolding 400 km Cyclotron Energy (MeV) Isotopes Produced Iabove Earth’s surface in recent weeks more than merit 18F, 99mTc, 11C, 13N, 15O, such a decision. Photographed on 2 December, NASA astronaut Best 15 15 64Cu, 67Ga, 124I, 103Pd Drew Morgan is seen installing a new coolant system for the Alpha Magnetic Spectrometer (AMS) – the unique cosmic-ray Best 15 + 123I, Best 20u/25 20, 25–15 detector masterminded by charm–quark co-discoverer Sam 111In, 68Ge/68Ga Matthew Ting of MIT and assembled by an international team at CERN. Chalmers AMS has been attached to the International Space Station (ISS) 123 Editor Best 30u Best 15 + I, since 2011 and initially was intended to operate for three years. 30 111 68 68 (Upgradeable) In, Ge/ Ga Never designed to be serviceable, some 25 bespoke tools had Greater production of to be developed for the procedure, which involved four high- profile extravehicular activities (EVAs) and years of preparation Best 35 35–15 Best 15, 20u/25 isotopes involving hundreds of , engineers and scientists on 201 81 81 plus Tl, Rb/ Kr t h e g r o u n d. It i s d e e m e d o n e o f t h e m o s t c o m pl e i nt e r v e nt i o n s 82 82 123 67 in space since repairs to the Hubble Space Telescope and will Virtuoso Attached to a robotic arm of the ISS on 2 December, Sr/ Rb, I, Cu, Installation of Best 70 MeV Best 70 70–35 81 keep AMS operating until the end of the decade. ESA’s Luca Parmitano handles the new pump system for AMS. Kr + research Cyclotron at INFN, Legnaro, Italy Equipped with a transition-radiation detector, a silicon t r a c k e r e m b e d d e d i n a 0.15 T m a g n e t, a t i m e- o f-fl i g ht d e t e c t or, e x i s t i n g c o ol i n g b o x . O n 2 D e c e m b e r, d u r i n g t h e c r u c i a l “E VA3”, ring-imaging Cherenkov detector and an electromagnetic calo- Morgan and Parmitano successfully connected the lines to the r i m e t e r, A M S l o o k s l i k e s o m e t h i n g y o u w o u l d fi n d u n d e r g r o u n d new pump system and, as the Courier we nt to pre ss, a fi n a l E VA at the business-end of a particle beam. In the pristine envi- t o c h e c k t h e c o n n e c t io n s w a s pl a n n e d for m id-Ja nu a r y. T h e n e x t ronment of space, the 7.5 tonne apparatus tracks and measures issue (and on cerncourier.com as events unfold) will feature a from the depths of the , and so far its 300,000 f ul l repor t on t he unprecedented A M S i nter vent ion a nd offer a The BG-75 Biomarker Generator is a revolutionary 400 MeV Rapid Cycling Medical Synchrotron channels have clocked up almost 150 billion charged cosmic taste of this unique experiment’s latest results. development in radio-pharmaceutical production for Proton-to-Carbon Heavy Ion Therapy: r a y s w it h e n e r g i e s u p t o t h e m u l t i-TeV r a n g e. It s p e r c e nt-l e v e l that delivers a single or batch dose of 18F-FDG, and results, in particular showing a clear excess in the expected In this issue number of at high energies, contradict conventional On the subject of intriguing data, this issue takes a closer look 18 Intrinsically small beams facilitating additional advanced F biomarkers on demand. beam delivery with precision understanding (CERN Courier December 2016 p26). A further 10 at anomalous nuclear-decay results reported recently by the The system provides integration of all components So far its years of operation should allow AMS to make conclusive state- “Atomki” experiment, which have been widely reported to needed to produce and qualify PET biomarkers Small beam sizes – small magnets, 300,000 ments on t he orig in of t he une x pected obser v at ions. herald the discovery of a fifth (p7), and explores the wider channels have To that end, on 2 November 2019 an Antares rocket lifted off value of anomalies to phenomenologists (p37). On p39 theorist into a single, self-contained system that occupies light gantries – smaller footprint clocked up f r o m Wa l l o p s I s l a n d, V i r g i n i a, c a r r y i n g n e w C O 2 cooling pumps Joh n E l l i s sur ve ys t he st at us a nd f ut ure of t he fie ld, w h i le our for the AMS tracker, following the failure of three of the four orig- fe a t u r e “W h o or d e r e d a l l o f t h a t?” d e s c r i b e s a t t e m p t s t o s ol v e a fraction of the space required by conventional Highly efficient single turn extraction almost solutions, simplifying the implementation of PET. i n a l p u m p s. O n 15 No v e m b e r M or g a n a n d E u r o p e a n S p a c e A g e n c y the flavour puzzle (p23). KATRIN’s quest for the neutrino mass Efficient extraction – less shielding 150 billion astronaut Luca Parmitano (pictured above right) successfully (p28), outreach for visually impaired audiences (p33), careers in charged removed and jettisoned the AMS debris , and, one week visual effects (p45) and the latest results from the LHC experi- Flexibility – heavy ion beam therapy cosmic rays later, the pair cut through eight stainless-steel lines to isolate the ments (p15) are other highlights of this first issue of the 2020s. ( and/or carbon), beam delivery modalities Reporting on international high-energy physics

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Nuclear physics Rekindled Atomki anomaly merits closer scrutiny Atomki A large discrepancy in nuclear decay rates X–e – coupling in the range (1.3–4.2) × 10–4. spotted four years ago in an experiment “The Atomki anomaly could be an exper- in Hungary has received new experimen- imental effect, a nuclear-physics effect tal support, generating media headlines or something completely new,” com- about the possible existence of a fifth ments NA64 spokesperson Sergei Gni- force of nature. nenko. “Our results so far exclude only a In 2016, researchers at the Institute of fraction of the allowed parameter space Nuclear Research (“Atomki”) in Debre- for the X , so I’m really interested cen, Hungary, reported a large excess in seeing how this story, which is only in the angular distribution of e+e– pairs just beginning, will unfold.” Last year, created during nuclear transitions of researchers used data from the BESIII excited 8Be nuclei to their ground state experiment in China to search for direct (8Be* → 8Be γ; γ → e+e–). Significant peak- X-boson production in electron– like enhancement was observed at large collisions and indirect production in J/ψ angles measured between the e+e– pairs, d e c a y s – fi n d i n g n o s i g n a l. K r a s z n a h or kay corresponding to a 6.8σ surplus over the and colleagues also point to the poten- expected e+e– pair-creation from known tial of beam-dump experiments such as processes. The excess was soon interpreted PADME in Frascati, and to the upcoming by theorists as being due to the possible D a r k L i g ht e x p e r i m e nt at Je ffe r s o n L a b - emission of a new boson X with a mass of oratory, which will search for 10–100 MeV 16.7 MeV decaying into e+e– pairs. dark photons.

In a preprint published in October 2019, Future view Atomki’s new high-resolution LaBr3 spectrometer, Theorist Jonathan Feng of the Univer- the Atomki team has now reported a sim- which will record gamma–gamma pairs from excited nuclei. sity of California at Irvine, who’s group

ilar excess of events from the electro- Atomki proposed the X-boson hypothesis in magnetically forbidden “M0” transition 2016, says that the new 4He results from in 4He nuclei. The anomaly has a statis- Atomki support the previous 8Be evidence tical significance of 7.2σ and is likely, of a new particle – particularly since the claim the authors, to be due to the same e x c e s s i s o b s e r v e d a t a s l i g ht l y d i ffe r e nt “X17” particle proposed to explain the e+e– opening angle in 4He (115 degrees) earlier 8Be excess. than it is in 8Be (135 degrees). “If it is an experimental error or some nuclear- Quality control physics effect, there is no reason for the “We were all very happy when we saw excess to shift to different angles, but if this,” says lead author Attila Kraszna- it is a new particle, this is exactly what is horkay. “After the analysis of the data expected,” says Feng. “I do not know of a really significant effect could be any inconsistencies in the experimen- observed.” Although not a fully blinded tal data that would indicate that it is an analysis, Krasznahorkay says the team X-factor expected, say theorists. For one, such experimental effect.” has taken several precautions against The Atomki team a particle would have to “know” about In 2017, theorists Gerald Miller at bias and carried out numerous cross- with the apparatus the distinction between up and down the University of Washington and Xilin checks of its result. These include checks used for the latest and thus electroweak symme- Zhang at Ohio State concluded that, if for the effect in the angular correlation 8Be and 4He results, try breaking. Being a , the the Atomki data are correct, the orig- of e+e– pairs in different regions of the which detects e+e– X17 would constitute evidence for a new inal 8Be excess cannot be explained by energy distribution, and assuming dif- pairs from the force. It could also be related to the dark- nuclear-physics modelling uncertainties. ferent beam and target positions. The de-excitation of problem, write Krasznahorkay and But they also wrote that a direct com- paper does not go into the details of nuclei produced by co-workers, and has the right properties parison to the e+e– data is not feasible systematic errors, for instance due to firing protons at to help resolve the discrepancy between due to “missing public information” possible nuclear-modeling uncertainties, different targets . measured and predicted values of the about the experimental detector effi- but Krasznahorkay says that, overall, the anomalous . ciency. “Tuning the normalisation of result is in “full agreement” with the Last year, the NA64 collaboration at our results reduces the confidence level results of the Monte Carlo simulations CERN reported results from a direct search of the anomaly by at least one standard performed for the X17 decay. for the X boson via the bremsstrahlung deviation,” says Miller. As for the latest While it cannot yet be ruled out, the reaction eZ → eZX, the absence of a signal Atomki result, the in 4He existence of an X boson is not naively placing the first exclusion limits on the is more complicated than 8Be because s

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NEWS ANALYSIS NEWS ANALYSIS

two nuclear levels are involved, explains The Hungarian team is now planning It would be a new particle,” says Feng, who too was Policy Miller, making it difficult to carry out an on repeating the measurement with a most helpful d o u b t f u l a t fi r s t. “B ut a t t h i s p oi nt, w hat 8 analysis analogous to the Be one. “For new gamma-ray coincidence spec- for other we need are new ideas about what can Physics tops finance in economic impact 4He there is also a background pair- trometer at Atomki (see main image), cause this anomaly. The Atomki group production mechanism and interference w h i c h t h e y s a y m i g ht h e l p t o d i s t i n g u i s h groups to step has now found the effect in two differ- e ffe c t t h a t i s n o t m e nt io n e d i n t h e p aer, between the vector and the pseudoscalar forward ent decays. It would be most helpful for Physics-based industries generate over Physics flies from manufacturing (42.5%), information much of which is devoted to the theory interpretation of the X17. Meanwhile, other groups to step forward to confirm 16% of total turnover and more than 12% The EPS- and communication (14.1%), and profes- a n d o t h e r f ut u r e e x p e r i m e nt s,” h e s a y s. a project called New JEDI will enable or refute their results.” of overall employment in Europe, top- commissioned s i o n a l, s c i e nt i fic a n d t e c h n i c a l a c t i v it i e sin “I think the authors would have been an independent verification of the8 Be ping contributions from the financial report claims that physics-based fields such as architecture, better served if they presented a fuller a n o m a l y a t t h e A R A M IS-S C A L P f a c i l it y Further reading services and retail sectors, according to physics makes a net and R&D (14.1%). Germany account of their data because, ultimately, (O r s a y, F r a n c e) d u r i n g 2020, fol l o w e d b y J Feng et al. 2016 Phys. Rev. Lett. 117 071803. a report published by the European Phys- contribution to the showed by far the highest percentage of t h i s i s a n e x p e r i m e nt a l i s s u e. C o n fi r m- d i r e c t s e a r c h e s b y t h e s a m e g r o u p for t h e J Jiang et al. 2019 Eur. Phys. J. C 79 404. ical Society (EPS). The analysis, carried European economy turnover from physics-based industries ing or refuting this discovery by future existence of the X boson, in particular A J Krasznahorkay et al. 2019 out by UK consultancy firm Cebr (Centre of at least €1.45 (29%), followed by the UK (14.2%), nuclear experiments would be extremely in other light systems, at the arXiv:1910.10459. for Economics and Business Research), trillion per year. (12.9%) and Italy (10.4%). important. A monumental discovery GANIL-SPIRAL2 facility in Caen, France. A J Krasznahorkay et al. 2016 Phys. Rev. reveals that physics makes a net contri- Taking into account “multiplier could be possible.” “M a n y p e o pl e a r e s c e p t ic a l t h a t t h i s i s Lett. 116 042501. bution to the European economy of at least impacts” that capture the knock-on €1.45 trillion per year, and suggests that e ffe c t o f g o o d s a n d s e r v ic e s o n t h e w id e r A ntim Atter physics-based sectors are more resilient economy, the analysis found that for than the wider economy. every €1 of physics-based output, a total ’ “To give some context to these num- of €2.49 is generated throughout the EU BASE tests antimatter s dark side bers, the turnover per person employed economy. The employment multiplier is in the physics-based sector substantially higher still, meaning that for every job in S Ul mer mer Ul S A fi r s t- o f-it s-k i n d e x p e r i m e nt a t C E RN determined a time-averaged frequency outperforms the construction and retail physics-based industries, an average of has brought and antimatter o f t h e a nt i pr o t o n’s pr e c e s s io n o f a r o u n d sectors, and physics-based labour pro- 3.34 jobs are supported in the economy as to face. The fundamental nature of 80 M H z w it h a n u n c e r t a i nt y o f 1 20 mHz. ductivity (expressed as gross value added a whole by these industries. dark matter, inferred to make up around No s i g n s o f r e g u l a r v a r i a t i o n s w e r e fo u n d, per employee) was significantly higher physics-based industries as those where While the report does not assess the a quarter of the universe, is unknown, producing the first laboratory con- than in many other broad industrial and workers with some training in physics impact of different sub-fields of physics, as is the reason for the observed cosmic s t r a i nt s o n t h e e x i s t e n c e o f a n i nt e r a c t i o n business sectors, including manufactur- would be expected to be employed and it is clear that high-energy physics is a i m b a l a n c e b e t w e e n m a t t e r a n d a nt i m a t- between antimatter and a dark-matter ing,” stated EPS president Petra Rudolf of where the activities rely heavily on the major contributor, says former EPS pres- t e r. I n v e s t i g a t i n g p o t e nt i a l l i n k s b e t w e e n candidate. The BASE data constrain the the University of Groningen. “Our hope theories and results of physics to achieve ident Rüdiger Voss of CERN. “The sheer the two, researchers working on the – interaction parameter is that the message conveyed by the EPS their commercial goals, following the Sta- scale and technological complexity of Antibaryon Symmetry Experi- (a factor in the matrix element inversely through the study performed by Cebr tistical Classification of Economic Activ- big-science projects, and the thousands ment (BASE) at CERN, in collaboration proportional to the postulated coupling will be inspiring for the future, both at it i e s i n t h e E u r o p e a n C o m m u n it y (N AC E). of highly skilled people that they pro- w it h m e m b e r s o f t h e He l m h ol t z I n s t it ut e between and ) to European and national levels, making a Based on several different measures of duce, makes , astronomy at Mainz, have reported the first labora- be above 0.1 GeV for an axion mass of convincing case for the support for phys- economic growth and prosperity, the and other research based on large-scale tory search for an interaction between 2 × 10–23 and above 0.6 GeV for an axion ics in all of its facets, from education to analysis found that physics-based goods f a c i l it ie s s i g n i fic a nt c o nt r i b ut or s t o t he a nt i m a t t e r a n d a d a r k-m a t t e r c a n d i d a t e: m a s s o f 4 × 10–17 eV, a t 95% c o n fid e n c e. For research, to business and industry.” and services contributed an average of European economy – not to mention the the axion. Mystery meets relies on single-particle -transition c o m p a r i s o n, s i m i l a r e x p e r i m e nt s u s i n g The Cebr analysis examined public- 44% of all exports from the 28 European fact that these are the subjects that often Axions are extremely light, spinless mystery s p e c t r o s c o p y – c o m p a r a bl e t o p e r for m- matter instead of antimatter achieve domain data in 31 European countries for Union (EU) countries during the relevant draw young people into science in the that were originally proposed in The BASE ing NMR with a single antiproton – limits of above 10 and 1000 TeV for the t he si x-year period 2011–2016. It defined period. The three major contributions were first place.” the 1970s to resolve the strong charge– experiment at whereby individual antiprotons stored same mass range – demonstrating M Brice/CERN parity problem of quantum chromo- CERN’s Antiproton in a Penning trap are spin-flipped from that a major violation of established AccelerAtors in December 2018, extensive upgrades of dynamics and, later, were predicted by Decelerator o n e s t a t e t o a n o t h e r (CERN Courier M a r c h charge-parity-time symmetry would CERN’s accelerator complex and exper- theories beyond the . showing two 2018 p25). An observed variation in the be implied by any signal given the cur- CERN updates iments have been taking place. The pre- B e i n g s t a bl e, a x io n s pr o d u c e d d u r i n g t h e cryostats (orange) precession frequency over time could r e nt B A SE s e n s it i v it y. T h e c ol l a b or a t i o n LHC schedule accelerator chain is being entirely reno- Bi g B a n g w o u l d s t i l l b e pr e s e nt t h r o u g h- flanking a provide evidence for the nature of dark also derived limits on six combinations v a t e d a s p a r t o f t h e L HC I nj e c t or s U p g r a d e o ut t h e u n i v e r s e, p o s s i bl y a c c o u nt i n g for superconducting matter and, if antiprotons have a stronger of previously unconstrained Lorentz- project, and new equipment is being dark matter or some portion of it. In this magnet, in which c o u pl i n g t o t h e s e p a r t i c l e s t h a n pr o t o n s and CPT-violating coefficients of the The LHC will restart in May 2021, mark- installed in the LHC, while development

c a s e, E a r t h w o u l d e x p e r ie n c e a “ w i n d” o f a multi-Penning do, such a matter–antimatter asymmetric n o n-m i n i m a l St a n d a rd M o d e l e x t e n s i o n. ing the beginning of Run 3, announced of t he HL-LHC’s Nb 3Sn magnets contin- gravitationally interacting dark-matter trap is used to coupling could provide a link between “We have not observed any oscillatory the CERN management on 13 December. ues above ground. On the morning of 13 particles that would couple to matter and manipulate dark matter and the s i g n a t u r e, h o w e v e r, o u r A L P–a nt i pr o t o n Beginning two months after the initially December, civil engineers made the junc- antimatter, and periodically modulate antiprotons. in t he universe. c o u pl i n g l i m it s a r e m u c h m or e s t r i n g e nt planned date, Run 3 will be extended by tion between the underground facilities at their fundamental properties, such as “We’ve interpreted these data in the than limits derived from astrophysical one year, until the end of 2024, to max- Points 1 and 5 of the accelerator – linking their magnetic moment. However, no framework of the axion-wind model observations,” says BASE spokesperson imise physics data taking. Then, during Breakthrough Lucio Rossi (HL-LHC project leader), Frédérick t h e H L-L HC t o t h e L HC, a n d m a r k i n g t h e evidence of such an effect has so far where light axion-like particles (ALPs) Stefan Ulmer of RIKEN, who is optimistic long-shutdown three between 2025 and Bordry (director for accelerators and technology), latest project milestone (see image). been seen in laboratory experiments o s c i l l a t e t h r o u g h t h e g a l a x y, a t f r e q u e n- that BASE will be able to improve the mid-2027, all of the equipment needed for (CERN Director-General) and Oliver Brüning (deputy HL-LHC project “The HL-LHC is in full swing and the with ordinary matter, setting stringent cies defined by the ALP mass,” explains sensitivity of its axion search. “Future t h e h i g h-lu m i n o s it y c o n fi g u r a t i o n o f t he leader) celebrate the HL-LHC tunnel breakthrough on 13 December. machine and civil engineering is on limits on the microscopic properties of lead author and BASE co-spokesperson studies, with a 10-fold improved fre- LHC (HL-LHC) and its experiments will track,” says Lucio Rossi, HL-LHC pro- cosmic axion-like particles. C h r i s t i a n Sm or r a o f R I K E N i n Ja p a n. “T h e quency stability, longer experimental be i nsta l led. The HL-LHC is sc heduled to components, even entire subdetectors, ject leader. “The schedule is drawn up in The BASE team has now searched for particles couple to the spins of Stand- campaigns and broader spectral scans come into operation at the end of 2027 and often working at the limits of current a global way, taking into account every t h e p h e n o m e n o n i n a nt i m a t t e r v i a m e a s- a r d M o d e l p a r t i c l e s, w h i c h w o u l d i n d u c e at higher frequency resolution, will allow to run for up to a decade. Its factor-five technology, to increase their physics reach. aspect of the machine, experiment and urements of the precession frequency frequency modulations of the Larmor u s t o i n c r e a s e t h e d e t e c t i o n b a n d w i d t h.” or more increase in levelled luminosity is The extra time incorporated into the new infrastructure readiness, entirely with the of the antiproton’s magnetic moment, precession frequency.” driving ambitious detector upgrade pro- schedule will enable the collaborations to aim to maximise the physics. The overall w h i c h it i s a bl e t o d e t e r m i n e w it h a f r a c- A c c r u i n g a r o u n d 1000 m e a s u r e m e nt s Further reading grammes among the LHC experiments. ready themselves for Run 3 and beyond. H L-L HC t i m e t a bl e i s fle x i bl e i n t h e s e n s e t io n a l pr e c i s io n o f 1.5 × 10–9. T h e t e c h n iq u e over a three-month period, the team C Smorra et al. 2019 Nature 575 310. The experiments are replacing numerous Since the start of long-shutdown two that it will depend on actual results.”

8 CERN COURIER JANUARY/FEBRUARY 2020 CERN COURIER JANUARY/FEBRUARY 2020 9

CCJanFeb20_NewsAnalysis_v3.indd 8 18/12/2019 15:37 CCJanFeb20_NewsAnalysis_v3.indd 9 18/12/2019 15:37 CERNCOURIER www. V o l u m e 6 0 N u m b e r 1 J a n u ary /F e b r u a r y 2 0 2 0 CERNCOURIER.COM NEWS ANALYSIS AI SOLUTIONS FOR YOUR

AstrowAtch BIG SCIENCE PROJECTS MAGIC spots epic gamma-ray burst DEVELOPING TODAY THE TOOLS FOR THE FUTURE Gamma-ray bursts (GRBs) are the bright- Munich MPI Wagner, ASPERA/R est electromagnetic events in the uni- OF ACCELERATORS verse since the Big Bang. First detected in 1967, GRBs have been observed about once per day using a range of instru- ments, allowing astrophysicists to gain a deeper understanding of their origin. As often happens, 14 January 2019 saw the detection of three GRBs. While the first two were not of particular interest, the ARTIFICIAL INTELLIGENCE FOR OPERATIONS unprecedented energy of photons emitted by the third – measured by the MAGIC •Beamline parameters optimization telescopes – provides a new insight into • Virtual machines and simulators these mysterious phenomena. The study of GRBs is unique, both •Reinforcement learning for accelerator control systems because GRBs occur at random locations • Deep neural network solutions for beam prediction and times and because each GRB has dif- ferent time characteristics and energy spectra. GRBs consist of two phases: a MOI AI FOR PARTICLE ACCELERATORS prompt phase, lasting from hundreds of milliseconds to hundreds of seconds, •Fully integrated AI framework for accelerator control which consists of one or several bright • Machine learning technology for mission-critical designs bursts of hard X-rays and gamma-rays; Burning bright The MAGIC telescope with guidance lasers switched on, and (below) a colour image taken by fol l o w e d b y a s i g n i fic a nt l y w e a k e r “a f ter- the Hubble Space Telescope of the location where GRB 190114C took place. •Real-Time interlocks and protection systems glow” phase that can be observed at lower energies ranging from radio to X-rays 2019 al. et Acciari NASA/ESA/V from this interaction produces the after- and lasts for periods up to months. glow observed at X-ray, optical and radio energies. However, some of these syn- Origins chrotron photons subsequently undergo Since the late 1990s, optical observations inverse Compton with the same h ave con fi r me d b ot h t h at GR Bs h app en , allowing them to reach TeV in other galaxies and that longer dura- energies. These measurements by MAGIC tion GRBs tend to be associated with s h o w, for t h e fi r s t t i m e, t h a t t h i s m echa- supernovae, strongly hinting that they nism does indeed occur. Given the many result from the death of massive stars. observations in the past where it wasn’t BPM Controller for RAON Accelerator EPICS ported Step-Motor Controller Bespoke Electronics for Particle Shorter GRBs, meanwhile, have recently observed, this appears to be yet another • 16 RF inputs and 4 BPM processors • Fast and stable control of up to Accelerators: been shown to be the result of - feat ure t hat differs bet ween GRBs. per controller eight motors • Position and phase resolution better • Compact design with Ethernet •BPM and LLRF Controllers star mergers thanks to the first joint The MAGIC results were published in than 5 μm and 0.1º communication •Step-motor, HV and Vacuum Controllers observations of a GRB with a gravita- an issue of Nature that also reported a • Embedded EPICS IOC and Channel • Embedded EPICS IOC, Channel tional wave in 2017. While this discovery of similar emission in a dif- Access Access event is often regarded as the start of ferent GRB by another Cherenkov tel- Software and Hardware Solutions for multi-messenger , the escope: the High Energy Stereoscopic Integrated Control: recent detection of GRB190114C lying System (H.E.S.S) in Namibia. While the •Distributed control systems & SCADA: 4.5 billion light-years from Earth adds measurements are consistent, it is inter- EPICS, WinCC, LabView y e t a n o t h e r m e s s e n g e r t o t h e fie l d o f GR B esting to note that the measurements by •PLC engineering: Siemens, Beckoff, astrophysics: TeV photons. H.E.S.S were made 10 hours after that TwinCAT The MAGIC telescopes on the island of detectors, the MAGIC telescopes started particular GRB, showing that this type L a P a l m a m e a s u r e t h e C h e r e n k o v r a d i a- repointing within a few tens of seconds of emission can also occur at much later •FPGA solutions tion produced when TeV photons induce of the onset of the GRB. In the next half time scales. With two new large-scale electromagnetic showers after interact- hour, the telescopes had observed around Cherenkov observatories – the Large Interlocks and Safety Systems: ing with the Earth’s atmosphere. During 1000 high-energy photons from the High Altitude Air Shower Observatory •Mission-critical systems for fusion the past 15 years, MAGIC has discovered a source. This emission, which has long in China and the global Cherenkov Tel- reactors and accelerators range of astrophysical sources via their been predicted by theorists, is shown by escope Array – about to commence data LLRF Controller for PAL X-FEL Accelerator Vacuum Controller • Excellent stability performance of • Integrated and compact (2U) control •High-dependable solutions for emission at these extreme energies. How- the collaboration to be the result of the taking, the field of GRB astrophysics can 0.02% (amplitude) and 0.03o (phase) of beamline vacuum instrumentation occupational safety ever, detecting the emission from GRBs “synchrotron self-Compton” process, now expect a range of new discoveries. • Independent channel amplifier • Up to 20 valves, 8 motors and gauge has remained elusive, despite more than whereby high-energy electrons acceler- control control (RS232) 100 attempts and the theoretical predic- ated in the initial violent explosion inter- Further reading • Embedded EPICS IOC and Channel • Control of up to 64 motors (RS485) tions that such emissions could exist. act with magnetic fields produced by the H Abdalla et al. 2019 Nature 575 464. Access • Embedded EPICS IOC, Channel Access On 14 January, based on an alert c ol l i s i o n b e t w e e n t h e s e e j e c t a a n d i nt e r- MAGIC Collab. 2019 Nature 575 455. provided by space-based gamma-ray stellar matter. The synchrotron emission MAGIC Collab. 2019 Nature 575 459. mobiis.com/en [email protected]

10 CERN COURIER JANUARY/FEBRUARY 2020

CCJanFeb20_NewsAnalysis_v3.indd 10 18/12/2019 15:38 CERNCOURIER www. V o l u m e 6 0 N u m b e r 1 J a n u ary /F e b r u a r y 2 0 2 0 CERNCOURIER.COM NEWS Supermicro DIGEST ESRF used by ATLAS. Although the data- nets, with yokes and beam pipes selection requirements are fixed, straightened by a delicately cali- Systems Help and results with the open likeli- brated brute-force deformation, to hoods cannot include the sim- house 120 m-long optical cavities.

ESA/Pla nc k L eg ac y 2018 ulation of possible new physics Should laser light be converted to signals in the detector, they will axion-like particles in the magnetic give theorists a quick assessment field, these particles would pass Capture the First of the potential of their new the- through a light-blocking wall and Detail of the CMB anisotropy. ories. An initially unplanned fruit could then be observed converting The first beam to circulate at ESRF’s of rewriting ATLAS software for back into photons in subsequent new storage ring. Crisis for cosmology? machine-learning frameworks, superconducting magnets. ALPS data on the cosmic micro- the releases should also ensure that II will benefit from both increased Extremely brilliant beginning Ever Images of a wave background (CMB) have been analyses survive developments in length and improved optical tech- Electron beams first circulated reinterpreted to favour a closed software and remain repeatable nology, in part thanks to work on in the Extremely Brilliant Source universe at more than 99% con- long into the future. gravitational-wave interferome- (EBS) on 2 December, almost two fidence, in contradiction with the ters. Data taking will begin in 2021. years after the installation of the flat universe favoured by the estab- Sendai statement affirms ILC upgraded 844 m-long storage ring lished ΛCDM model of cosmology 430 s c ie nt i s t s a t t e n d i n g t h e I nt e r- Ireland eyes CER N membership began. The first of its kind, with (Nat. Astron. 2019/arXiv:1911.02087). national Workshop on Future Lin- A cross-party committee of the an increased X-ray brightness and In their new fit to Planck’s 2018 ear Colliders in Sendai, Japan, on legislature of the Republic of Ireland c o h e r e nt flu x 100 t i m e s h i g h e r t han data release, Eleonora Di Valentino 31 October asserted their commit- has unanimously recommended before, EBS is t he c ul m i nat ion of a (Manchester), Alessandro Melchi- ment to building the International Ireland become an Associate decade-long programme to upgrade orri (La Sapienza) and Joe Silk Linear Collider (ILC), the strong Member State of CERN, to help the European Synchrotron Radi- (Oxford) exchanged an anoma- s u p p or t o f t h e l o c a l c o m m u n it y, a n d train the next generation of sci- ation Facility (ESRF) in Grenoble, lously large lensing amplitude (a the project’s maturity and readiness e nt i s t s a n d e n g i n e e r s, a n d d e v e l o p Fr a nce, a nd ensure Europe’s lead- phenomenological parameter that for implementation. The ILC’s cost industry opportunities. Alongside ing position in the light-source rescales the gravitational-lensing estimate is on a sound technical M a l t a a n d L u x e m b o u r g, I r e l a n d i s world (CERN Courier December 2018 potential in the CMB power spec- basis as the key superconducting one of only three EU countries that p17). The facility also boasts new t r um) for a h ig her energ y densit y. RF technology has been success- d o n o t h a v e a n y for m a l a g r e e m e nt X-ray beamlines, instrumenta- In addition to the lensing anom- fully demonstrated in the European with the laboratory. “Ireland has tion and computing, to facilitate a l y, w h i c h l e a d s t o i n c o n s i s t e n c i e s X F E L i n G e r m a n y, a s s e r t e d t h e p a r- a strong particle-physics com- nanometre-scale studies ranging between large and small scales, ticipants, who argue that the case mu n it y a nd CER N wou ld we lcome from biology to paleontology. On the flat interpretation is already for a Higgs-boson factory is more s t r o n g e r i n s t it ut io n a l l i n k s, w h ic h 15 D e c e m b e r, t h e m a c h i n e a c h i e v e d pl a g u e d b y a 4.4σ tension with the compelling than ever given recent we believe would be mutually a world-record horizontal beam latest determination of the Hub- LHC results. beneficial,” says Charlotte War- emittance of 308 pm. ble constant using observations a k a u l l e, C E R N’s d i r e c t or for i nt e r- of the recession of Cepheid stars national relations. A new era of quantum biolog y (arXiv:1903.07603) - a tension that A natural biomolecule has been Data Processing and Storage for Black Hole Imaging g r o w s t o 5.4 σ in a closed universe. M M ayer/DESY Beauty enter the fray caught acting like a quantum wave The inconsistencies between data L HC b h a s l a u n c h e d a n e w o ffe n s i v e for t h e fi r s t t i m e (a r X i v:1910.1 4538). The first imaging of the event horizon aided by the expanded computing power of sets signal “a possible crisis for i n t h e e x pl or a t i o n o f l e p t o n-fl a v o u r Armin Shayeghi of the Universit y cosmology”, argue the authors. universality (arXiv:1912.08139). of Vienna and colleag ues demon- for a black hole involved an international today’s IT infrastructure. Processing of the 4 Following previous results that strated quantum interference in ATLAS opens likelihoods up hinted that e+e- pairs might be of gramicidin - a nat- partnership of eight radio telescopes with petabytes (PB) of data generated in the project In a move sure to excite phenom- DESY’s Joachim Mnich signs the first produced at a greater rate than μ+μ- ural antibiotic made up of 15 amino major data processing at leading research in 2017 for the original imaging utilized enologists, ATLAS has published ALPS II magnet to be installed. p a i r s i n B m e s o n d e c a y s t o K (*)ℓ+ℓ-, acids. The team fired a series of “open likelihoods” with full ana- t he st ud y br i ng s b a r yon de c ay s to short laser pulses to knock the institutes in the US and Germany. The servers and storage systems, with many lytical complexity for two recent First A LPS II magnet installed bear on the subject for the first biomolecules into a beam of s u p e r s y m m e t r y a n a l y s e s: a s e a r c h T h e fi r s t m a g n e t h a s b e e n i n s t a led time. The collaboration measured a t o m s, a n d u s e d T a l b o t-L a u i nt e r- contribution of the brilliant scientists was of these servers coming from Supermicro. for bottom-squark pair production in the upgraded Any-Light- the ratio of branching fractions for ferometr y to obser ve an interfer- 0 – + – 0 – + – (arXiv:1908.03122) and a search for Particle-Search (ALPS II) exper- Λ b → pK e e and Λ b → pK μ μ to be ence pattern consistent with a de +0.18 direct stau production in events iment, which will continue the 1.17 -0.16 (st at) ± 0.07 (s yst). Thoug h Broglie wavelength for the grami- Learn more at www.supermicro.com/blackhole with two hadronic s e a r c h for a x i o n-l i k e p a r t i c l e s, h i d- highly suppressed in the Stand- cidin of 350 fm. Though such effects (arXiv:1911.06660). While parti- den photons and “mini-charged” ard Model, the decays could be have previously been observed in cle searches by the LHC experi- particles. Located at DESY in Ham- affected by the existence of new larger molecules, this is the first ments already provide a wealth of burg, in a straight section of the particles (CERN Courier May/June demonstration with fragile bio- Featuring 2nd Generation Intel® Xeon® Scalable processors numerical information, theorists t u n n e l w h e r e H E R A o p e r a t e d u nt i l 2019 p9). T h e s t u d y a l s o c o n s t it ut e s molecules, and paves the way will for the first time have access 2007, ALPS II will reuse 24 of that the first observation of the decay for the optical spectroscopy of 0 – + – to the full underlying data model machine’s superconducting mag- Λ b → pK e e . en z y mes and DNA.

CERN COURIER JANUARY/FEBRUARY 2020 13

CCJanFeb20_News digest_v4.indd 13 18/12/2019 15:48 CERNCOURIER www. V o l u m e 6 0 N u m b e r 1 J a n u ary /F e b r u a r y 2 0 2 0 CERNCOURIER.COM ENERGY Got radiation? FRONTIERS Reports from the Large Collider experiments See what you’ve been missing CMS Crystal calorimeter hones Higgs mass

Though a free parameter in the Stand­ the energy and momenta of the elec­ CMS preliminary 35.9 fb–1 (13 TeV) ard Model, the mass of the trons, and photons necessary for 16000 is important for both theoretical and H→γγ all categories the measurement. ^ S/(S+B) weighted experimental reasons. Most pecu­ mH = 125.8 GeV The most recent contribution to this data liarly from a theoretical standpoint, 12000 work was a measurement of the mass S+B fit our current knowledge of the masses in the di­ channel using data B component of the Higgs boson and the 8000 collected at the LHC by the CMS collab­ ± 1σ imply that the quartic coupling of the ± 2σ or a t i o n i n 2016 (fi g u r e 1). T h i s m e a s ure­ Higgs vanishes and becomes negative 4000 ment was made using the lead–tungstate tantalisingly close to, but just before, crystal calorimeter, which uses approx­ the Planck scale. There is no established 0 imately 76,000 crystals, each weighing S/( S+ B) weighted events/GeV reason for the Standard Model to perch about 1.1 kg, to measure the energy of the 400 B component subtracted near to this boundary. The implication photons. A critical step of this analysis is that the vacuum is almost but not 0 was a precise calibration of each crystal’s quite stable, and that on a timescale response using electrons from Z­boson –400 substantially longer than the age of the decay, and accounting for the tiny dif­ 100 110 120 130 140 150 160 170 180 universe, some point in space will tun­ ference between the electron and photon mγγ (GeV) Photo courtesy of EUROfusion. Website: www.euro-fusion.org nel to a lower energy state and a bubble showers in the crystals. Photo courtesy of EUROfusion. Website: www.euro-fusion.org of true vacuum will expand to fill the Fig. 1. The relatively small Higgs-boson resonance can be seen This new result was combined with universe. Meanwhile, from an experi­ in its decay to two photons, above the falling background of earlier results obtained with data col­ mental perspective, it is important to photons from other processes (top) and with the estimated lected between 2011 and 2016. One Imaging in radiation environments just got easier continually improve measurements background subtracted (bottom). measurement was in the decay channel so that uncertainty on the mass of the to two Z bosons, which subsequently Higgs boson eventually rivals the value CMS preliminary decay into electron or muon pairs, and –1 –1 of its width. At that point, measuring Run 1: 5.1 fb (7 TeV) + 19.7 fb (8 TeV) total stat. only another was a measurement in the With superior capabilities for operating in radiation environments, the MegaRAD cameras provide –1 the Higgs­boson mass can provide an 2016: 35.9 fb (13 TeV) di­photon channel made with earlier excellent image quality well beyond dose limitations of conventional cameras, and are well suited total (stat. only) independent method to determine the Run 1 H→γγ 124.70 ± 0.34 (± 0.31) GeV data. The 2011 and 2012 data combined for radiation hardened imaging applications Higgs­boson width. The Higgs­boson yield 125.06 ± 0.29 GeV. The 2016 data Run 1 H→zz*→4I 125.59 ± 0.46 (± 0.42) GeV width is sensitive to the existence of yield 125.46 ± 0.17 GeV. Combining these possible undiscovered particles and is Run 1 combined 125.06 ± 0.29 (± 0.27) GeV yields CMS’s current best precision of expected to be a few MeV according to 125.35 ± 0.15 G eV (fi g u r e 2). T h i s n e w pre­ 2016 H→γγ 125.78 ± 0.26 (± 0.18) GeV the Standard Model. cise measurement of the Higgs­boson 2016 H→zz*→4I 125.26 ± 0.21 (± 0.19) GeV The CMS collaboration recently mass will not, at least not on its own, announced the most precise measure­ 2016 combined 125.46 ± 0.17 (± 0.13) GeV lead us in a new direction of physics, but

ment of the Higgs­boson mass achieved Run 1 + 2016 125.35 ± 0.15 (± 0.12) GeV it is an indispensable piece of the puzzle thus far, at 125.35 ± 0.15 GeV – a preci­ of the Standard Model – and one fruit sion of roughly 0.1%. This very high of the increasing technical mastery of 122 123 124 125 126 127 128 129 130 precision was achieved thanks to an the LHC detectors. mγγ (GeV) enormous amount of work over many MegaRAD3 produce color MegaRAD1 produce KiloRAD PTZ radiation years to carefully calibrate and model Fig. 2. Measurements of the Higgs-boson mass by the CMS Further reading or monochrome video up to monochrome video up to resistant camera with the CMS detector when it measures collaboration. The most recent is the H → γγ channel with 2016 data. CMS Collab. 2019 CMS­PAS­HIG­19­004. 3 x 106 rads total dose 1 x 106 rads total dose Pan/Tilt/Zoom LHCb

In the United States: International: For customer service, call 1-800-888-8761 For customer service, call [01) 315-451-9410 Opening g ambit for LHC b in t he Vcb puzzle To fax an order, use 1-315-451-9421 To fax an order, use [01) 315-451-9410 incl –3 Email: [email protected] Email: [email protected] There is a longstanding puzzle concern­ complementary methods. One uses the The averages |Vcb| = (42.19 ± 0.78) × 10 , differs from ing the value of the Cabibbo–Kobayashi– inclusive rate of b­hadron decays into differ by three the average of results using the exclusive |, which |excl = (39.25 ± 0.56) 10–3, by Maskawa matrix element |Vcb final states containing a c hadron and a standard approach, |Vcb × describes the coupling between charm charged ; the other measures the approximately three standard deviations. Find out more at thermofisher.com/cidtec and beauty quarks in W± interactions. This r a t e o f a s p e c i fic (e x c lu s i v e) s e m i l e p t o n i c B deviations So far, exclusive determinations have 0 *– + + – fundamental parameter of the Stand­ d e c a y, e.g. B → D μ νμ. The world average been carried out only at e e colliders, s ard Model has been measured with two of results using the inclusive approach, using B 0 and B+ decays. Operating at 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 JANUARY/FEBRUARY 2020 15

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ENERGY FRONTIERS ENERGY FRONTIERS

0 (*)– + the ϒ(4S) resonance, the full decay kin- also uses B → D μ νμ as a normalisation indicates no suppression in the QGP, involve a large fraction of the 207 or so cantly more suppressed than those that Jets with ematics can be determined, despite the mode, which has the key advantage that whereas a value below one indicates a in each lead nucleus. RAA is pre- consist of a single small-radius jet. This hard internal undetected neutrino, and the total number m a n y s y s t e m a t i c e ffe c t s c a n c e l i n t h e r a tio. suppressed jet yield. The measurement sented separately for large-radius jets observation is qualitatively consistent ALEPH [1997 PLB 395 373] splittings lose of B produced, needed to measure W it h t h e for m f a c t or s a n d r e l a t i v e e ffic i en- is corrected for background fluctua- with a single isolated high- with the hypothesis that jets with hard CLEO [1999 PRL 82 3746] more energy |Vcb|, is known precisely. The situation is Belle [2016 PRD 93 032006] CLN cy-corrected yields in hand, obtaining |Vcb| tions and instrumental resolution via sub-jet and for those with multiple sub- internal splittings lose more energy, and BGL more challenging in a hadron collider – BaBar [2009 PRD 79 012002] requi res on ly a fe w more i nput s: br a nc h- an unfolding procedure. jets in three intervals of the splitting provides a new perspective on the role of but the LHCb collaboration has just com- BaBar [2010 PRL 104 011802] ing fractions that were well measured at The figure shows RAA for large-radius scale √d12. As expected, jets are increas- jet structure in jet suppression. Further 0 0 pleted an exclusive measurement of |Vcb| ALEPH [1997 PLB 395 373] the B-factories, and the ratio of Bs and B jets as a function of the average number ingly suppressed for more head-on col- progress will require comparison with 0 based, for t he first t ime, on B s decays. CLEO [2002 PRL 89 081803] production fractions measured at LHCb. of participating nucleons – a measure of lisions (figure 1). More pertinently to theoretical models. The exclusive determination of |Vcb| OPAL [2000 PLB 482 15] The values of |Vcb| obtained are the centrality of the collision, as glanc- this analysis, and for all centralities, –3 –3 relies on the description of strong-in- OPAL [2000 PLB 482 15] (41.4 ± 1.6) × 10 a nd (4 2.3 ± 1.7) × 10 in the ing collisions involve only a handful of yields of large-radius jets that consist of Further reading teraction effects for the b and c quarks DELPHI [2001 PLB 510 55] CLN and BGL parametrisations, respec- nucleons, whereas head-on collisions s e v e r a l s u b -j e t s a r e fo u n d t o b e s i g n i fi- ATLAS Collab. 2019 ATLAS-CONF-2019-056. bound in mesons, the so-called form DELPHI [2004 EPJ C33 213] tively. These results are compatible with factors (FF). These are functions of the BaBar [2008 PRD 77 032002] each other and agree with previous meas- ALICE recoil momentum of the c in the BaBar [2008 PRL 100 231803] urements with exclusive decays, as well as b-meson , and are calculated BaBar [2009 PRD 79 012002] t h e i n c lu s i v e d e t e r m i n a t i o n (fi g u r e 1). T h is 0 A LICE probes ex t reme elect romag net ic fields CLN u s i n g n o n-p e r t u r b a t i v e Q C D t e c h n iq u e s, Belle [2019 PRD 100 052007] BGL new technique can also be applied to B CLN such as lattice QCD or QCD sum rules. A BaBar [2019 PRL 123 091801] BGL decays, giving excellent prospects for new 0 CLN key advantage of semileptonic Bs decays, LHCb [LHCb-PAPER-2019-041] BGL |Vcb| measurements at LHCb. They will also When two lead nuclei collide in the LHC Fig. 1. The directed 0/+ compared to B decays, is that their FF benefit from expected improvements at at an energy of a few TeV per , 0 flow v 1 of positively ALICE 3 + v1(D ) exclusive average (HFLAV 2019) 0 (*)– 0.5 10 × v (h ) Pb–Pb, √s NN = 5.02 TeV can be more precisely computed. Recently, Belle II to a key external input, the B → D an extremely strong of 1 – 0 and negatively 3 – v1(D ) + 14 15 10 × v (h ) the FF parametrisation used in the exclu- inclusive average (HFLAV 2019) μ νμ branching fraction. Belle II’s own the order 10 –10 T is generated by the 1 charged

sive determination has been considered measurement of |Vcb| is also expected to spectator protons, which pass by the (left, scaled by a to be a possible origin of the inclusive– have reduced systematic uncertainties. In collision zone without breaking apart factor 103 for 1

v 0 exclusive discrepancy, and comparisons 10 20 30 40 addition, new lattice QCD calculations for in inelastic collisions. The strongest visibility) is three –3 |V | [10 ] *– between the results for |Vcb| obtained cb the full range of the D recoil momentum yet probed by scientists, this magnetic orders of magnitude 5–40% 0 using different parametrisations, such are expected soon and should give valua- field, and in particular the rate at which 10–40% smaller than for D p > 0.2 GeV/c –0 as that by Caprini, Lellouch and Neubert Fig. 1. Summary of all exclusive measurements of |V |. The new ble constraints on the form factors. This it decays, is interesting to study since T and D mesons cb 3 < pT < 6 (GeV/c) 0 –0.5 bars: stat. uncert. (CLN) and that by Boyd, Grinstein and LHCb measurement (red triangles) uses Bs decays, while all others synergy between theoretical advances, it probes unexplored properties of the boxes (filled/empty): syst. uncert. (corr./uncorr.) not feed-down corrected (right). In both Lebed (BGL), are considered a key check. are obtained from B0 or B+ decays. The error bars show the total Belle II and LHCb (and its upgrade, due to quark– plasma (QGP), such as its cases, the difference 0.5 Both parametrisations are employed (outer) and statistical (inner, when present) uncertainties. s t a r t i n 202 1) w i l l v e r y l i k e l y s a y t h e fi n a l electric conductivity. In addition, chiral Δv1 bet ween the 0 (*)– + – by LHCb in a new analysis of B → D μ ν When not stated, the measurement is obtained using the CLN word on the |V | puzzle. phenomena such as the chiral magnetic 3 + – 0 0 charge-conjugate s s μ cb 10 × [v1(h ) – v1(h )] v1 (D ) – v1(D ) decays, using a novel method that does not parametrisation. The exclusive average does not include the effect are expected to be induced by the species as a function re q u i re t he m om e nt u m o f p a r t ic le s ot he r new LHCb results or BaBar [2019 PRL 123 091801]. The average Further reading strong fields. Left–right asymmetry in of pseudorapidity η – + than Ds and μ to be estimated. The analysis of the inclusive determinations is also reported. LHCb Collab. LHCb-PAPER-2019-041. the production of negatively and posi- 1 0 (bottom panels) has tively charged particles relative to the Δ v an opposite slope to ATLAS collision reaction plane is one of the 5–40% 10–40% model calculations. observables that is directly sensitive to pT > 0.2 GeV/c 3 < pT < 6 (GeV/c) electromagnetic fields. This asymmetry, More plasma quenching seen in wide jets –4 –1 dΔv /dη = [1.68±0.49 (stat) ± 0.41 (syst)] ×10 dΔv /dη = [4.9±1.7 (stat) ± 0.6 (syst)] ×10 called directed flow (v1), is sensitive to –0.5 1 1 t w o m a i n c o m p e t i n g e ffe c t s: t h e L or e nt z –0.5 0 0.5 –0.5 0 0.5 Hard-scattering processes in hadronic data taken at the LHC in 2018 and cor- force experienced by charged particles ηη collisions generate parton showers – ATLAS preliminary responding pp data collected in 2017, (quarks) propagating in the magnetic –1 –1 h i g h l y c ol l i m a t e d c ol l e c t i o n s o f q u a r k s Pb + Pb 1.72 nb , pp 257 pb , 5.02 TeV ATLAS has measured large-radius fie l d, a n d t h e Fa r a d a y e ffe c t – t h equark single sub-jet –1 and that subsequently frag- 1.5 jets by clustering smaller-radius jets current that is induced by the rapidly negatively charged hadrons is shown dΔv1/dη = 4.9 ± 1.7 (stat) ± 0.6 (syst) × 10 – 14 < √d 12 < 20 Gev ment into hadrons, producing jets. In with transverse momenta pT > 35 G eV. d e c r e a s i n g m a g n e t i c fie l d. C h a r m q u a r ks in the bottom-left panel. The η slope positive at 2.7σ s i g n i fic a n c e (l o w e r-r i g ht 29 < √d 12 < 41 Gev ultra-relativistic nuclear collisions, (This procedure suppresses contribu- are produced in the early stages of heavy- i s found to b e dΔv 1/dη = 1.68 ± 0.49 (stat) panel). Also, in this case, the sign of the 59 < √d –4 the parton shower evolves in a hot and 12 < 84 Gev tions from the underlying event and ion collisions and are therefore more ± 0.41 (syst) × 10 – positive at 2.6σ sig- observed slope is opposite with respect dense quark–gluon plasma (QGP) cre- excludes soft radiation, so that the focus s t r o n g l y a ffe c t e d b y t h e e l e c t r o m a g n e tic n i fic a n c e. T h i s m e a s u r e m e nt h a s a sim- to model calculations, suggesting that 1.0 ated by the collision. Interactions of remains on hard partonic splittings.) fields than lighter quarks. ilar order of magnitude to recent model the relative contributions of the Lorentz AA the partons with the plasma lead to R The sub-jets are further re-clustered The ALICE collaboration has recently calculations of the expected effect for and Faraday effects in those calculations reduced parton and jet energies, and in order to obtain the splitting scale, probed this effect by measuring the charged , but with the opposite sign. are not correct. m o d i fie d pr o p e r t ie s. T h i s p h e n o m e n o n, √d , which represents the transverse d i r e c t e d flo w, v , for charged hadrons and The right-hand panels show the same Together with recent observations at 12 – 1 known as jet quenching, results in the 0.5 momentum scale for the hardest split- D0/D0 mesons as a function of pseudora- analysis for the neutral charmed mesons RHIC, these LHC measurements provide – suppression of jet yields – a suppres- ting in the jet – a measure of the angular pidity (η) in mid-central lead–lead col- D0 (cu–) and D0 (–cu) (centrality class an intriguing first sign of the effect of

sion that is hypothesised to depend on separation between the high-momen- lisions at √sNN = 5.02 TeV. Head-on (most 10–40%). The measured directed flows are the large magnetic fields experienced in the structure of the jet. High-momen- |y| < 2.0 200

16 CERN COURIER JANUARY/FEBRUARY 2020 CERN COURIER JANUARY/FEBRUARY 2020 17

CCJanFeb20_EnergyFrontiers_v4.indd 16 18/12/2019 15:50 CCJanFeb20_EnergyFrontiers_v4.indd 17 18/12/2019 15:50 CERNCOURIER www. V o l u m e 6 0 N u m b e r 1 J a n u ary /F e b r u a r y 2 0 2 0 CERNCOURIER.COM CERNCOURIER.COM ADVERTISING FEATURE FIELD MIM electromagnetic flowmeter in stainless-steel NOTES desig n – compact or remote version up to +1 40 °C – Reports from events, conferences and meetings with IO-Link from KOBOLD T wisTors and Loops

Kobold continues to design and some extent, resisting the trend wand measurement, monitoring, and When twistors met loops develop quality measuring and temptation to incorporate unnecessary transmitting. Dual configurable

analytical instrument products, and features and over complicated outputs can be selected such as Loop quantum and twistor theory F Viadotto picture of quantum physical space. Cur- have now launched their compact flow software. analogue, frequency, pulse, and have a lot in common. They both have rent applications of loop gravity include meter, the MIM with even more switching, but also switched dosing as a main objective, early cosmology, where the possibility of versatile features. With factories and controlled start/stop for the they both discard conventional space– a bounce replacing the Big Bang has been time as the cornerstone of physics and extensively studied using loop-gravity within the Kobold Group experiencing dosing function. As further product they have both taken major inspiration methods, and black holes, where the the- well over one hundred years of trading, development, the MIM is now also from renowned British mathematician ory’s amplitudes can be used to study the Kobold has an enviable and extensive available in remote version for medium . Interaction between non-perturbative transition at the end wealth of technical knowledge and up to +140°C. Together the two communities has been mini- of the Hawking evaporation. experience to draw upon when with IO-Link, MIM is world first to offer mal so far, however, due to their dis- tinct research styles: mathematically A fertile union developing new products. At the such characteristics among magnetic oriented in twistor theory but focused The communities working in twistors concept stage, Kobold will often draw inductive flowmeters. on empirical support in loop gravity. and loops share technical tools and upon the experience of their This separation was addressed in early conceptual pillars, but have evolved international sales offices to establish September 2019 at a conference held at independently for many years, with a framework of practical features and the Centre International de Rencontres different methods and different inter- Mathématiques (CIRM) at the Luminy mediate goals. But recent developments functionality, and thus produce an campus in Marseille, where around 100 discussed at the Marseille conference saw instrument which is suitable and From the MIM concept Kobold have researchers converged for lively debates twistors appearing in formulations of the compliant for an international market produced a high quality and versatile designed to encourage cross-fertilisation loop-gravity amplitudes, confirming the place. This indeed was the process compact flow meter for measuring between the two research lines. fertility and the versatility of the twistor for MIM. conductive liquids, ensuring suitability idea, and raising intriguing questions Space–time dissolves about possible deeper relations between for a wide range of industrial Both twistor theory and loop gravity the two theories. applications. Heavy duty construction regard conventional smooth general- The conference was a remarkable suc- in stainless steel provides a clean and Typically with an electromagnetic flow relativistic space–time as an approximate cess. It is not easy to communicate across robust instrument module. The design meter there are no moving parts in the and emerging notion. Twistor theory was research programmes in contemporary of the 90° step indexable TFT display measuring device and this can be a key proposed by Roger Penrose as a general Twist and shout treat space–time as the background fundamental physics because a good geometric framework for physics, with Roger Penrose’s talk on which physics happens, but rather part of the field is stalled in communi- screen is clever, yet simple and robust, advantage in many industrial the long-term aim of unifying general was the highlight of as a dynamical entity itself, satisfy- t i e s bl o c k e d b y c o n fl i c t i n g a s s u m p t i o n s, ensuring suitability for multi applications. In principle the induced relativity and . The the Twistors and ing quantum theory. The conventional ingrained prejudices and seldom-ques- directional flow applications, voltage is picked up by two sensing main idea of the theory is to work on Loops conference. smooth general relativistic space–time tioned judgments, making understand- programmable from the touch screen. electrodes which are in with the null rays, namely the space of the e merges i n t he c l a ssic a l (ℏ → 0) limit, in ing one another difficult. The vibrant possible path that a light ray can follow the same manner as a smooth electro- atmosphere of the Marseille conference A nice feature of the TFT display screen the measuring agent and sent to the in space–time, instead of the manifold magnetic field satisfying the Maxwell cut through this. is that it can be used by operators measuring amplifier. The flow rate will of the points of physical space–time. equations emerges from the Fock space The best moment came during wearing gloves. Unlike some of the TFT be calculated based on the cross Space–time points, or events, are then of the photons in the classical limit of Penrose’s talk. Towards the end of a long screens on the market using inclination sectional area of the pipe. A key seen as derived objects: they are given quantum electrodynamics. Similarly, the and dense presentation of new ideas sensors for screen position, the MIM advantage of this measuring principle by compact holomorphic curves in a full dynamics of classical general rel- towards understanding the full space of complex three-fold: twistor space. It is ativity is recovered from the quantum the solutions of Einstein’s theory using screen remains clear and stable in use, is that the measurement is not remarkable how much the main equa- dynamics of loop gravity in the suitable twistors, Roger said rather dramatically a reminder of Kobold’s instinctive depending on the process liquid and its tions of fundamental physics simplify limit. The transition amplitudes of the that now he was going to present a new, preference for simplified practical material properties such as density, when formulated in these terms. The theory are finite in the ultraviolet and big idea that might lead to the twistor functionality and reliable service. viscosity and , however, of twistors has its roots in are expressed as multiple integrals over version of the full Einstein equations be mindful that the flowing media must the 19th century Klein correspondence in non-compact groups. The theory pro- – but at that precise moment the slide projective geometry, and modern twistor vides a compelling picture of quantum projector exploded in a cloud of smoke, As you would expect, Kobold’s MIM have a minimum conductivity. theory has had a strong impact on pure space–time. A basis in the Hilbert space with sparks flying. We all thought for a Innovative design and quality have instrument incorporates all the m a t h e m a t ic s, f r o m d i ffe r e nt i a l g e o me- of the theory is described by the math- moment that a secret power of the uni- try and representation theory to gauge ematics of the spin networks: graphs verse, worried about being unmasked, become hallmarks of all Kobold practical control and display features Could allying theories and integrable systems. with links labelled by SU(2) irreducible had interfered. Could allying twistors manufactured products but required in most process applications twistors refreshingly, during their concept stage as standard. This includes Loop gravity, on the other hand, is representations, independently intro- and loops be dangerous? a background-independent theory of and loops be duced by Penrose in the early 1970s in an Kobold are clearly applying focus to bidirectional measuring, combined quantum gravity. That is, it does not dangerous? attempt to a fully discrete combinatorial Carlo Rovelli Aix-Marseille University. practical ease of functionality and to flow, temperature, and volume www.kobold.com

CERN COURIER JANUARY/FEBRUARY 2020 19

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FIELD NOTES FIELD NOTES

Colloquium Y Ding CERN’s turns 60 CERN-PHOTO-5612555 On 24 November 1959, CERN’s Proton The PS has proven to be a flexible Synchrotron (PS) first accelerated beams design, with huge built-in potential. to an energ y of 24 GeV. 60 years later, it T h o u g h t h e fi r s t e x p e r i m e nt s w e r e per- is still at the heart of CERN’s acceler- for m e d w it h i nt e r n a l t a r g e t s, e x t r a c t i o n s ator complex, delivering beams to the t o e x t e r n a l t a r g e t s w e r e s o o n a d d e d t o t h e fi x e d-t a r g e t p h y s ic s pr o g r a m m e a n d t he design, and further innovative extraction L HC w it h i nt e n s it i e s e x c e e d i n g t h e i n it i a l schemes were added through the years. s p e c i fic a t i o n s b y or d e r s o f m a g n it u d e.To O n t h e a c c e l e r a t or s id e, t h e i nt e n s it y w a s Back to Bloomington The eighth CPT and Lorentz Symmetry meeting took place at Indiana University. celebrate the anniversary a colloquium progressively ramped up, with the com- was held at CERN on 25 November 2019, missioning of the PS Booster in 1972, the physics, astrophysics and gravitational urements of antimatter acceleration. erage vast distances to limit cumulative with PS alumni presenting important r e p e a t e d i n c r e a s e o f t h e i nj e c t i o n e n e r g y, physics continue to place exquisitely tight The commissioning of ELENA, CERN’s effects such as the rotation of a polarisa- phases in t he li fe of t he accelerator. a n d m a n y i m pr o v e m e nt s i n t h e P S it s e l f. b o u n d s o n t h e S M E c o e ffic i e nt s, m o t i v a t e d 30 m-circumference antiproton decel- t i o n a n g l e. I n t h e g r a v it y s e c t or, S M E c o e f- The PS is CERN’s oldest operating Through the years more and more users by the intriguing prospect of finding a eration ring, promises larger quantities ficient bounds were presented from the accelerator, and, together with its sister requested beam from the PS, for example crack in the Lorentz symmetry of nature o f r e l a t i v e l y s l o w-m o v i n g a nt i pr o t o n s i n 2015 g r av it y-w ave detec t ion by t he LIG O mac h i ne, t he A lter nat i ng Gr ad ient Sy n- the EAST area, antiproton physics, and a (CERN Courier December 2016 p21). support of this work. collaboration, as well as from observations chrotron (AGS) at Brookhaven National neut ron t ime-of-flight facilit y. C o m p a r i s o n s b e t w e e n m a t t e r a n d a nt i- Lorentz violation can occur inde- o f p u l s a r s, c o s m ic r a y s a n d o t h e r p h e n o m- L a b or a t or y i n t h e US, o n e o f t h e t w o ol d e s t W it h t h e c o m m i s s i o n i n g o f t h e ISR, SP S, matter offer rich prospects for testing pendently in each sector of the particle ena w it h sig nals t hat are propor t ional to st i l l oper at i ng acceler ators i n t he world. P.S. I love you Construction of the tunnel for the Proton LEP and LHC machines, t he PS took on a Lorentz symmetry, because individual world, and par ticipants discussed exist- t h e t r a v e l d i s t a n c e. S y m m e t r y-br e a k i n g B o t h d e s i g n s a r e b a s e d o n t h e i n n o v a t i v e Synchrotron took place from 1955 to 1957. new role as an injector of protons, anti- SME coefficients can be isolated. The i n g a n d f ut u r e l i m it s o n S M E c o e ffic i e nt s s i g n a l s a r e a l s o s o u g ht i n m a t t e r-g r a v it y

concept of the alternating gradient, or CERN-PHOTO-5612555 proton s, le pton s a nd ion s, w h i le c ont i n- AEgIS, ALPHA, ASACUSA, ATRAP, BASE b a s e d o n t h e m u o n g-2 e x p e r i m e nt a t Fe r- interactions with test masses, and here strong-focusing, principle developed by uing its own physics programme. A new a n d g B A R c ol l a b or a t io n s a t C E R N, a s w e l l m i l a b, n e ut r i n o o s c i l l a t i o n s a t D a y a B a y i n CPT’19 included discussions of short- Ernest Courant, Milton Stanley Living- challenge was the delivery of beams for a s o n e s a t o t h e r i n s t it ut io n s, a r e w or k i n g China, oscillations in Frascati, and range spin-dependent gravity and neu- ston, Ha r t l a nd Snyder a nd Joh n Ble we t t. the LHC: these beams need to be trans- to develop the challenging technology for on decay using the Jagello- tron-interferometry physics. This technique allowed a significant v e r s e l y v e r y d e n s e (“br i g ht”), a n d h a v e a such tests. Several presenters discussed n ia n PET detec tor (CERN Courier Novem- The SME has revealed uncharted reduction in the size of the vacuum cham- longitudinal structure that is generated Penning traps – devices that confine ber 2018 p17), to name a few. Dozens of territory that requires theoretical and bers and magnets, and unprecedented using the different radio-frequency sys- charged particles in a static electromag- L or e nt z-s y m m e t r y t e s t s h a v e pr o b e d t h e experimental expertise to navigate. beam energies. In 1952 the CERN Coun- tems of t he PS, w it h t he PS t hereby con- netic field – for storing and mixing the photon sector of the SME with table-top CPT’19 showed that there is no shortage cil endorsed a study for a synchrotron t r i b ut i n g it s f a i r s h a r e t o t h e s u c c e s s o f t h e ingredients for antihydrogen, the pro- devices such as atomic clocks and res- of with the adventurous spirit based on the alternating-gradient prin- L HC. A n d t h e r e a r e m or e c h a l l e n g e s a h e a d. duction of antihydrogen, spectroscopy for onant cavities, and with astrophysical to e x plore t his front ier f ur t her. c i pl e, a n d c o n s t r u c t i o n o f a m a c h i n e w it h The LHC’s high-luminosity upgrade pro- t h e h y p e r fi n e a n d 1 S–2 S t r a n s it io n s, a nd polarisation measurements of sources a d e s i g n- e n e r g y r a n g e f r o m 20 t o 30 GeV g r a m me dem a nd s b ea m pa r a me ters out t he prospects for inter ferometric meas- s uc h a s a c t i ve g a l a c t ic nuc le i, w h ic h le v- Neil Russell Northern Michigan University. w a s a p pr o v e d i n O c t o b e r 1953. It s d e s i g n, of reach for today’s injector complex, manufacture and construction took place motivating the ambitious LHC Injectors JENAS f r o m 1954 t o 1959. P r o t o n s m a d e fi r s t t u r n s Upgrade Project (CERN Courier October APPEC, ECFA and Not impossibly t h e w orl d’s m o s t p o w e r f u l i n s t r u m e nt for o n 16 S e p t e m b e r 1959, a n d o n 2 4 No v e m b e r 2017 p33). Installations are now in full tribal A Penrose ground-based gamma-ray astronomy. b e a m w a s a c c e le r at e d b e yo n d t r a n s it io n s w i n g, a n d R u n 3 w i l l t a k e C E R N’s P S i nt o NuPECC join forces triangle was used Organisational synergies related to and to an energy of 24 GeV. On 8 December a n e w p a r a m e t e r r e g i m e a n d i nt o a n o t h e r to symbolise how education, outreach, open science, open t h e d e s i g n e n e r g y o f 2 8.3 G eV w a s r e a c h e d Margherita The first combined-function magnet, named after interest ing c hapter in its li fe. astroparticle, s o f t w a r e a n d c a r e e r s w e r e a l s o i d e nt i fie d,

and the design intensity exceeded, at particle- Margherita Cavallaro (pictured here), was The first joint meeting of the European JENAS particle and and a diversity charter was launched by 3 × 1010 protons per pulse. completed in 1956, and is still in use today. Klaus Hanke CERN. 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 (E C FA), nuclear physics t h e t h r e e c o n s or t i a, w h e r e b y s t a t i s t ic s o n the Nuclear Physics European Collabo- are intertwined. relevant parameters will be collected at CPT’19 ration Committee (NuPECC), and the e a c h c o n fe r e n c e a n d w or k s h o p i n t h e t h r e e Astroparticle Physics European Consor- subfields. This will allow the communities Space–time symmetries scrutinised in Indiana tium (APPEC) took place on 14–16 Octo- to ver i f y how wel l we embr ace diversit y. b e r i n O r s a y, F r a n c e. M a k i n g pr o g r e s s i n As chairs of the three consortia, we The space–time symmetries of physics The SME br o u g ht 100 r e s e a r c h e r s t o g e t h e r f r o m 1 2 d i m e n s io n s a n d h i g h e r ord e r i n t h e fie l d s. domains such as dark matter, issued a call for novel expressions of demand that experiments yield identical has revealed to 16 May 2019 at the Indiana University One example is the Lorentz-breaking and gravitational waves increasingly a r t i fic i a l i nt e l l i g e n c e w e r e ju s t a h a n dful i nterest to t ac k le com mon c ha l lenges i n results under continuous Lorentz trans- C e nt e r for S p a c e t i m e S y m m e t r ie s, t o s a m- lagrangian-density term (k )μν(ψ– γ ψ) requires interdisciplinary approaches to of t he topics discussed. For example, t he s u bj e c t s a s d i v e r s e a s c o m p ut i n g a n d t h e uncharted VV μ for m at ion s – rot at ion s a nd b o o s t s – a nd ple a smorgasbord of ongoing SME studies. (ψ– γ ψ), which is quartic in the scientific and technological challenges, technological evolution of silicon photo- search for dark matter. Members of the territory ν under the discrete CPT transformation Most physics is described by oper- fieldψ . The coefficient k VV carries units a nd t he ne w Joi nt ECFA-NuPECC-A PPEC m u l t i pl i e r s, w h i c h a r e c a p a bl e o f m e a s u r- high-energy physics and related commu- (the combination of charge conjugation, that requires ators of mass dimension three or four o f G eV –2 a n d c o nt r ol s t h e o p e r a t or, w h i c h Seminar (JENAS) events are designed to ing single-photon light signals and can n it i e s c a n s u b m it t h e i r i d e a s, i n p a r t i c u l a r parity inversion and time reversal). The theoretical that are quadratic in the conventional has mass dimension six. Searches for reinforce links between astroparticle, operate at low voltage and in magnetic those concerning synergies in technology, Standard-Model Extension (SME) pro- and fields – for example the Dirac lagrangian L o r e n t z-s y m m e t r y b r e a k i n g s e e k n o n z e r o nuclear and par t icle physicists. fields, will be key both for novel calorim- As chairs physics, organisation and applications. – v id e s a f r a m e w or k for t e s t i n g t h e s e s y m- contains an operator ψ ∂̸ ψ (m a s s d i m e n- values for coefficients like k VV. In the 21 Jointly organised by LAL-Orsay, IPN- e t e r s a n d t i m i n g d e t e c t or s a t t h e h i g h-lu- of the three A PPE C, E C FA a n d Nu PE C C w i l l d i s c u s s a n d experimental – metries by including all operators that expertise to sion 3/2 + 1 + 3/2 = 4) and an operator ψ ψ y e a r s s i n c e t h e fi r s t C P T m e e t i n g, t h e oret- Orsay, CSNSM-Orsay, IRFU-Saclay and m i n o s it y L HC. T h e y w i l l a l s o b e u s e d i n t h e consortia, propose actions in advance of the next break them in an effective field theory. The (mass dimension 3/2 + 3/2 = 3), with the ic a l s t ud ie s h a ve u nc o ve re d ho w to w r ite - JENAS event in 2021. L PN H E-P a r i s, t h e i n a u g u r a l J E N A S m e e t C h e r e n k o v Te l e s c o p e A r r a y – a n o b s e r v a- we issued a fi r s t C P T a n d L or e nt z S y m m e t r y m e e ting, navigate latter controlled by an additional mass d o w n t h e m y r i a d o p e r a t or s t h a t d e s c r i b e i n g s a w 230 j u n i or a n d s e n i or m e m b e r s o f tory of more than 100 telescopes that will i n Bl o o m i n g t o n, I n d i a n a, i n 1998, fe a t u r e d coefficient – however, the search for hypothetical Lorentz violations in both the three communities discuss overlap- be installed at La Palma in the northern call for novel Jorgen D’Hondt ECFA chair, t he fi r st l i m it s on SM E co effic ie nt s. L ast fundamental symmetry violations may flat and curved space–times. Meanwhile, ping interests. Readout electronics, silicon hemisphere, and in the Atacama Desert expressions Marek Lewitowicz NuPECC chair and s y e a r’s e v e nt, t h e 8t h i n t h e t r i e n n i a l s e r i e s, n e e d t o e m pl o y o p e r a t or s o f h i g h e r m a s s experiments in particle physics, atomic photomultipliers, big-data computing and in the southern hemisphere, becoming of interest Teresa Montaruli APPEC chair.

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FIELD NOTES FEATURE THE FLAVOUR PROBLEM oey Tove A Higgs Couplings 2019 t/10 Last stop for the Higgs Couplings workshop WHO ATLAS-PHOTO-2019-016-3 Higgs-boson measurements are enter- ing the precision regime, with Higgs couplings to gauge bosons now meas- ured to better than 10% precision, and ORDERED its decays to third-generation measured to better than 20%. These and other recent experimental and theoreti- cal results were the focus of discussions at the eighth international Higgs Cou- ALL OF plings workshop, held in Oxford from 30 September to 4 October 2019. Making its final appearance with this moniker (it will be rebranded as Higgs 2020), the conference programme comprised 38 THAT? plenary and 46 parallel talks attended by 120 participants. b The first two days of the conference reviewed Higgs measurements, includ- c ing a new ATLAS measurement of ttH u production using Higgs-boson decays Explaining the bizarre pattern d t o le p t on s, a nd a d i ffe re nt i a l m e a s u re- s τ ment of Higgs-boson production in its of fermion types and masses e decays to W-boson pairs using all of the μ CMS data from Run 2. These measure- has led theorists to explore more ν1 ments showed continuing progress in ν2 ν3 GUTs coupling measurements, but the high- complex symmetry groups than light of the precision presentations was the Standard Model’s, with recent family a new determination of the Higgs-boson mass from CMS using its decays to two work sug gest i ng t hat t he “flavour Family affair The Standard Model offers no explanation for why the masses photons. Combining this result with Two towers constraint on the Higgs self-coupling of M o d e l e ffe c t i v e fie l d t h e or y, w h e r e new of quarks and leptons (represented by the heights of the towers) span at least previous CMS measurements gives a ATLAS and CMS –2.3 < κ < 10.3 times the Standard Model p a r t i c l e s a p p e a r a t s i g n i fic a nt l y h i g h e r scale” could be at a much lower λ 12 orders of magnitude. Grand unified theories (GU Ts) or a new “family” Higgs-boson mass of 125.35 ± 0.15 GeV, data are driving predict ion at 95% confidence. m a s s e s (~1 TeV or more). The calculations corresponding to an impressive rela- down uncertainties The theoretical programme of the in the effective field theory continue to energ y t ha n pre v iously t houg ht. symmetry, acting in the directions shown, may provide insights. tive precision of 0.12%. From the theory on the Higgs conference included an overview of advance, adding higher orders in QCD side, the challenges of keeping up with couplings. the broader context for Higgs physics, to more electroweak processes, and an he origin of the three families of quarks and lep- are Dirac or Majorana particles, the latter requiring the experimental precision were discussed. covering the possibility of generating analytical determination of the depend- tons and their extreme range of masses is a cen- neutrino and antineutrino to be related by CP conjugation) For example, the Higgs-boson pro- the observed matter–antimatter asym- ence of the Higgs decay width on the T t r a l my s t e r y of p a r t ic le p hy s ic s. A c c ord i n g t o t he and mixing is unclear, and many possible SM extensions duction cross section is calculated to m e t r y t h r o u g h a fi r s t- ord e r e l e c t r o w e a k theory parameters. Constraints on the Standard Model (SM), quarks and leptons come in complete have been proposed. the highest order of any observable in phase transition, as well as possibili- number and values of these parame- families that interact identically with the gauge forces, The discovery of neutrino mass and mixing makes the perturbative QCD, and yet it must be ties for generating the Yukawa coupling ters also continue to improve through leading to a remarkably successful quantitative theory flavour puzzle hard to ignore, with the fermion mass hier- predicted even more precisely to match matrices. In the so-called electroweak an expanded use of input measurements. de s c r i bi n g pr ac t ic a l ly a l l d at a at t he qua nt u m le ve l. The a rc h y n o w s p a n n i n g at le a s t 1 2 ord e r s o f m a g n it ud e, f r o m the expected experimental precision of scenario, the cooling The conference wrapped up with v a r io u s q u a r k a n d le p t o n m a s s e s a r e d e s c r i b e d b y h a v i n g the neutrino to the top quark. However, it is not only the the HL-LHC. universe developed bubbles of broken a look into the crystal ball of future One of the highest priority targets of electroweak symmetry with asymmet- detectors and colliders, with a sober- different interaction strengths with the Higgs doublet fe r m io n m a s s h ie r a rc h y t h at i s u n s e t t l i n g. T h e r e a r e n o w the HL-LHC is the measurement of the ric matter–antimatter interactions at ing yet inspirational account of detector (figure 1, le f t), a l s o le a d i n g t o q u a r k m i x i n g a n d c h a r g e- 28 free parameters in a Majorana-extended SM, including self-coupling of the Higgs boson, which the boundaries, with sphalerons in the requirements at the next generation of p a r it y (CP) v iol at i ng t r a n sit ion s i nvolv i ng s t r a nge, b ot- a whopping 22 associated with flavour, surely too many is expected to be determined to 50% electroweak-symmetric space con- colliders. To solve the daunting chal- tom and charm quarks. However, the SM provides no for a f u n d a m e nt a l t h e or y o f n at u r e. To r e s t at e Is id or Is a a c precision. This determination is based verting the resulting matter asym- lenges, the audience was encouraged understanding of the bizarre pattern of quark and lepton R a bi’s f a m o u s q ue s t io n fol lo w i n g t h e d i s c o v e r y o f t h e muo n on double-Higgs production, to which metry into a baryon asymmetry. The to be creative and explore new tech- masses, quark mi x ing or CP violation. in 1936: who ordered all of that? the self-coupling contributes when a matter-asymmetric interactions could nologies, which will likely be needed In 1998 the SM suffered its strongest challenge to virtual Higgs boson splits into two Higgs have arisen through Higgs-boson cou- to succeed. Various collider scenarios date with the decisive discovery of neutrino oscilla- A theory of flavour bosons. ATLAS and CMS have performed plings to fermions or gauge bosons, or were also presented in the context of tions resolving the atmospheric neutrino anomaly and There have been many attempts to formulate a theory extensive searches for two-Higgs pro- through its self-couplings. In the latter the European Strategy update, which the long-standing problem of the low flux of electron b e yo n d t h e S M t h at c a n a d d r e s s t h e fl a v o u r p u z z le s. M o s t duction using data from 2016, and at the case the source could be an additional will wrap up early next year. neutrinos from the Sun. The observed neutrino oscilla- attempt to enlarge the group structure of the SM describ- conference ATLAS presented an updated ATLAS electroweak singlet or doublet modify- The newly minted Higgs confer- THE AUTHOR self-coupling constraint using a com- ing the Higgs potential. ence will be held in late October or tions require at least two non-zero but extremely small ing the strong, weak and electromagnetic gauge forces: presented Stephen F King bination of single- and double-Higgs The broader interpretation of early November of 2020 in Stonybrook, neutrino masses, around one ten millionth of the electron SU(3) C × SU(2)L × U(1)Y (s e e “A t a s t e o f fl a v o u r i n e le m e nt a ry an updated School of Physics measurements and searches. Allowing Higgs-boson measurements and New York. mass or so, and three sizeable mi xing angles. However, p a r t ic le p h y s ic s” p a n e l). T h e b a s ic pr e m i s e i s t h at, u n l i k e and Astronomy, o n l y t h e s e l f- c o u pl i n g t o b e m o d i fie d b y self-coupling searches was discussed both in the case since the minimal SM assumes massless neutrinos, the in the SM, the three families are distinguished by some University of a factor κλ in the loop corrections yields a constraint of specific models and in the Standard Chris Hays University of Oxford. origin and nature of neutrino masses (i.e. whether they new quantum numbers associated with a new family or Southampton, UK.

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FEATURE THE FLAVOUR PROBLEM FEATURE THE FLAVOUR PROBLEM

Thus t he flavour scale is ver y unconstrained. A TASTE OF FLAVOUR IN PHYSICS To illustrate the unknown magnitude of the flavour Columbia Columbia University H H s c a le, c o n s id e r for e x a m ple t h e F N m e c h a n i s m, w h e r e M fl The origin of flavour can be . The left-handed

is associated with the breaking of the U(1)fl symmetry. traced back to the discovery of the (L) electron and neutrino form a

In the SM the top-quark mass of 173 GeV is given by a electron – the first elementary doublet under SU(2)L, while the Yukawa coupling times the Higgs vacuum expectation fermion – in 1897. Following right-handed electron is a singlet, value of 246 GeV divided by the square root of two. This the discovery of relativity with the doublet and singlet

c c implies a top-quark Yukawa coupling close to unity. The and quantum mechanics, carrying U(1)Y ψi ψj ψi ψj e x a c t v a lue i s not i mp or t a nt, w h at m at te r s i s t h at t he t o p the electron and the photon and the pattern repeating for the yij Yukawa coupling is of order unity. From this point of view, became the subject of the most second and third lepton families. the top quark mass is not at all puzzling – it is the other successful theory of all time: Similarly, the left-handed up fermion masses associated with much smaller Yukawa quantum electrodynamics (QED). and down quarks form doublets, couplings that require explanation. According to FN, the However, the smallness of the and so on. The electroweak φ φ fermions are assigned various U(1)fl charges and small electron mass (me = 0.511 MeV) SU(2)L × U(1)Y symmetry is

φ φ φ Yukawa couplings are forbidden due to a U(1)fl symmetry. compared to the mass of an spontaneously broken to U(1)QED T h e s y m m e t r y i s br o k e n b y t h e v a c uu m e x p e c t at io n v a lue o f has always intrigued physicists. by the vacuum expectation value a n e w “fl a v o n” fie ld <ϕ>, where ϕ i s a n e ut r a l s c a l a r u n d e r The mystery of the electron of the neutral component of a new

Fig. 1. Left: Yukawa couplings, yij, between the Higgs doublet, H, a left-handed t h e S M b ut c a r r ie s on e u n it o f U(1) fl c h a r g e. Sm a l l Yu k a w a mass was compounded by the doublet of complex c fermion, ψi, and the CP conjugate of a right-handed fermion, ψj . Right: how the couplings then originate from an operator (figure 1, right) discovery in 1936 of the muon fields called the Higgs doublet.

Yukawa coupling could arise effectively due to a contact interaction involving suppressed by powers of the small ratio <ϕ>/M fl (w h e r e M fl with a mass of 207 me but After spontaneous symmetry multiple flavon fields,ϕ . acts as a cut-off scale of t he contact interact ion). otherwise seemingly identical breaking, this results in massive

For example, suppose that the ratio <ϕ>/M fl is iden- properties to the electron. This charged W and neutral Z gauge

fl a v o u r s y m m e t r y g r o up, G fl, w h ic h i s t a c k e d o nt o t h e S M tified with the Wolfenstein parameter λ = sinθC = 0.225 led to quip “who bosons, and a massive neutral

g a u g e g r o up, e n l a r g i n g t h e s t r uc t u r e t o G fl × SU(3) C × SU(2)L (where θC is the Cabibbo angle appearing in the CKM ordered that?”. Four decades Good taste I I Rabi, who won the in Physics in 1944 for his scalar Higgs boson – a picture

× U(1) Y. The earliest ideas dating back to the 1970s include quark-mixing matrix). Then the fermion mass hierar- later, an even heavier version of discovery of nuclear magnetic resonance. triumphantly confirmed by radiative fermion-mass generation, first proposed by chies can be explained by powers of this ratio, controlled the electron was discovered, the experiments at CERN. 5 2 Weinberg in 1972, who supposed that some Yukawa by the assigned U(1)fl charges: me/mτ ∼ λ , mμ/mτ ∼ λ , tau lepton, with mass mτ = 17 mμ. and the heavyweight top and of weak interactions based on a To truly shed light on the 4 2 8 4 couplings might be forbidden at tree level by a flavour md/mb ∼ λ , m s/mb ∼ λ , m u/mt ∼ λ and m c/mt ∼ λ . This Yet the seemingly arbitrary bottom quarks (mt = 97 mτ and contact interaction between the Standard Model’s flavour puzzle,

symmetry but generated effectively via loop diagrams. shows how fermion masses spanning many orders of values of the masses of the mb = 2.4 mτ) of a third family. four fermions, with a coupling theorists have explored higher and Alternatively, the Froggatt–Nielsen (FN) mechanism in magnitude may be interpreted as arising from integer charged leptons are only part of It was also realised that the strength given by a dimensionful more complex symmetry groups

1979 a s s u m e d a n a d d it io n a l U(1) fl s y m m e t r y u n d e r w h ic h U(1) fl c h a r g e a s s i g n m e nt s o f le s s t h a n 10. Ho w e v e r, i n t h i s the story. It soon became clear different quark “flavours”, a constant GF, whose scale was than the Standard Model. The

t he quarks and leptons carr y v arious c harges. approach, Mfl m ay b e a ny w here f rom t he Pl a nc k s c a le to that hadrons were made from term invented by Gell-Mann and later identified with the mass of most promising approaches all 2 To account for family replication and to address the t h e e le c t r o w e a k s c a le b y a dju s t i n g <ϕ> s uc h t h at t h e r at io quarks that come in three colour Fritzsch, could undergo mixing the W boson: GF ∝ 1/mW. involve a spontaneously broken

q ue s t io n o f l a r g e le p t o n m i x i n g, t h e or i s t s h a v e e x plor e d λ = <ϕ>/M fl is held fi xed. charges mediated by gluons transitions. For example, at After decades of painstaking family or flavour symmetry. But

a l a r g e r n o n-A b e l i a n f a m i l y s y m m e- O n e p o s s i bi l it y for M fl, r e v ie w e d b y K a l a d i B a b u at O k l a- under a SU(3)C gauge theory, the quark level the radioactive observation, including the the flavour-breaking scale may lie

The discovery of try, SU(3) fl, where the three families homa State University in 2009, is that it is not too far quantum chromodynamics decay of a nucleus is explained discovery of parity violation, anywhere from the Planck scale are analogous to the three quark from the scale of grand unified theories (GUTs), of order (QCD). The up and down quarks by the transformation of a down whereby only left-handed to the electroweak scale, with neutrino mass and colours in quantum chromodynam- 1016 GeV, which is the scale at which the gauge couplings of the first family have intrinsic quark into an plus particles experience the weak grand unified theories suggesting ic s (Q C D). M a n y o t h e r e x a m ple s h a v e associated with the SM gauge group unify into a single masses m = 4 m and m = 10 m , an electron and an electron interaction, Fermi’s theory of a high flavour scale, while recent mixing makes the u e d e been proposed based on subgroups gauge group. The simplest unifying group, SU(5)GUT, w a s accompanied by the charm and antineutrino. Shortly after Pauli weak interactions and QED were hints of anomalies from LHCb and

flavour puzzle hard o f SU(3) fl, including discrete symme- proposed by Georgi and Glashow in 1974, following the strange quarks (mc = 12 mμ and hypothesized the neutrino in merged into an electroweak other experiments suggest a low

tries (figure 2, right). More recently, work of Pati and Salam based on SU(4) × SU(2) × SU(2) . ms = 0.9 m ) of a second family 1930, Fermi proposed a theory theory based on SU(2) × U(1)Y flavour scale. to ignore C L R μ L theorists have considered extra- Both these gauge groups can result from SO(10)GUT, w h ic h dimensional models in which the Higgs field is located was discovered by Fritzsch and Minkowski (and inde- at a 4D brane, while the fermions are free to roam over pendently by Georgi), while many other GUT groups and or s o m e m e c h a n i s m a s s o c i at e d w it h c o m p a c t i fic at io n o f i n 2017 t h at neut r i no m a ss e s m ig ht b e c omple x a n a ly t ic t h e e x t r a d i m e n s io n, o v e rl a p pi n g w it h t h e H i g g s fie ld i n s u b g r o up s h a v e a l s o b e e n s t ud ie d (fi g u r e 2, le f t). Ho w e v e r, e x t r a d i mensions, to be appl ied to t he flavour brea k i ng. functions called modular forms. The starting point of this s uc h a w a y a s t o r e s u lt i n h ie r a rc h ic a l Yu k a w a c o upl i n g s. GUT groups by themselves only unify quarks and leptons T hu s, i n s uc h t h e or ie s, t h e GU T a n d fl a v o u r/f a m i l y s ym- n o v e l id e a i s t h at n o n-A b e l i a n d i s c r e t e f a m i l y s y m m e t r ie s 16 St i l l ot her ideas i nc lude pa r t ia l compositeness i n wh ic h within a given family, and while they may provide an metry are both broken at or around M fl ∼ MGUT ∼ 10 GeV, may arise from superstring theory in compactified extra

fermions may get hierarchical masses from the mix- explanation for why m b = 2.4 mτ, as discussed by Babu, as widely discussed by many authors. In this case, it dimensions, as a finite subgroup of the modular symme- ing bet ween an elementar y sector and a composite one. t hey do not account for t he fer mion mass hierarc hies. w o u ld b e i m p o s s i ble g i v e n k n o w n t e c h n olo g y t o d i r e c t l y try of such theories (i.e. the symmetry associated with The possibilities are seemingly endless. However, all experimentally access the underlying theory responsible the non-unique choice of basis vectors spanning a given such theories share one common question: what is Broken symmetries for unification and flavour. Instead, we would need to e x t r a-d i men sion a l l at t ice). It fol low s t h at t he 4 D effe c-

the scale, Mfl, (or scales) of new physics associated A way around this, first suggested by Ramond in 1979, is to rely on indirect probes such as proton decay (a generic tive Lagrangian must respect modular symmetry. This, w it h flavour? combine GUTs with family symmetry based on the product pr e d ic t io n o f GU T s a n d h e n c e o f t h e s e e n l a r g e d S M s t r uc- Feruglio observed, implies that Yukawa couplings may

Since experiments at CERN and elsewhere have group G GUT × Gfl, with symmetries acting in the specific t u r e s pr o p o s e d t o e x pl a i n fl a v o u r) a n d /or c h a r g e d-le p t o n b e m o d u l a r for m s. S o i f t h e le p t o n s t r a n s for m a s t r i ple t s thoroughly probed the electroweak scale, all we can directions shown in the figure “Family affair”. In order flavour-violating processes such as μ → eγ (see CERN under some finite subgroup of the modular symmetry, say for sure is that, unless the new physics is extremely not to spoil the unification of the gauge couplings, the fla- Courier May/June 2019 p45). t hen t he Yukaw a coupl ings t hemselves must t r ansfor m

weakly coupled, M fl can be anywhere from the Planck v o u r-s y m m e t r y br e a k i n g s c a le i s o f t e n a s s u m e d t o b e c lo s e Ne w id e a s for a d d r e s s i n g t h e fl a v o u r pr o ble m c o nt i nue also as triplets, but with a well defined structure depend- s c a le (10 19 G eV ), w h e r e g r a v it y b e c o m e s i m p or t a nt, t o t h e t o t h e GU T br e a k i n g s c a le. T h i s a l s o e n a ble s t h e d y n a m ic s t o b e d e v e lo p e d. For e x a m ple, m o t i v at e d b y s t r i n g t h e or y, i n g o n o n l y o n e f r e e p a r a m e t e r: t h e c o m ple x m o d u lu s fie ld. electroweak scale at the mass of the W boson (80 GeV). o f w h at e v e r br e a k s t h e GU T s y m m e t r y, b e it H i g g s fie ld s Ferruccio Feruglio of the University of Padova suggested At a stroke, this removes the need for flavon fields and

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FEATURE THE FLAVOUR PROBLEM FEATURE THE FLAVOUR PROBLEM

with all couplings arising eff ectively from mixing with a vector-like fourth family. The considered model predicts, ma ke t he fl avour problem of t he SM worse. a p a r t f r o m t h e TeV s c a le le p t o q u a r k a n d/or Z′, a n d a s l i g ht l y E6 SU(3) heavier fourth family, extra fl avour-changing processes Link-up τ → μμμ. The model in its current form does not SU(5) × U(1) SO(10) SU(3)C × SU(3)L × SU(3)R Motivated by such considerations, it is tempting to Σ(168) Δ(96) SO(3) t h e q u a r k m a s s e s i n t e r m s o f t h e v e c t or-l i k e fo u r t h f a m i l y non-universality may be linked to a possible theory of m a s s e s, w h ic h a r e f r e e p a r a m e t e r s. C r uc i a l l y, t h e r e q u i r e d SU(4)C × SU(2)L × SU(2)R SU(5) fl avour. Several authors have hinted at such a connec- TeV scale Z′ mass is given by MZ′ ϕ> ~ TeV, which would fi x

tion, for example Riccardo Barbieri of Scuola Normale t h e fl a v o u r s c a le M fl ~ few TeV. In other words, if the hints Δ(27) T7 S4 A5 SU(3)C × SU(2)L × SU(2)R × U(1)B–L Superiore, Pisa, and collaborators have related these for fl a v o u r a n o m a l ie s h old up a s f u r t h e r d at a a r e c ol le c t e d observations to a U(2) fl avour symmetry in an eff ec- by the LHCb, Belle II and other experiments, the origin of tive theory framework. In addition, concrete models fl avour may be right around the corner.  SU(3) × SU(2) × U(1) A C L Y 4 have recently been constructed that directly relate the eff ective Yukawa couplings to the eff ective Further reading n recent and/or Z′ couplings. In such models the scale of new K S Babu 2009 arX iv:0910.2948. years F ig. 2 . Left: some GUT groups based on E or one of its subgroups. Right: some candidate family-symmetry groups based on SU(3) or one of its physics associated with the mass of the leptoquark R Barbieri et al. 2016 ur. Phys. . C 67. 6 anomaies subgroups, which admit irreducible triplet representations and thereby provide an explanation for three families and large lepton mixing. a n d /or a n e w Z′ m a y b e id e nt i fi e d w it h t h e fl a v o u r s c a le M F Feruglio 2017 arXiv:1706.08749. fl have aeared defi ned earlier, except that it should be not too far from the F Feruglio 2015 ur. Phys. . C 373. e, μ and τ interact identically with the gauge forces, and TeV s c a le i n ord e r t o e x pl a i n t h e a n o m a l ie s. To a c h ie v e t h e C D Froggatt and H B Nielsen 1979 ucl. Phys. 1 277. associated differ only in their masses, which result from having d e si re d l i n k, t he e ff e c t i ve le pto qua r k a nd/or Z′ c oupl i n g s H Georgi and S L Glashow 1974 Phys. Re. Lett. 438. ith LQ Zʹ different Yukawa couplings to the Higgs doublet. This m a y b e g e n e r at e d b y t h e s a m e k i n d s o f o p e r at or s r e s p o n- S F K ing 2019 arX iv:1905.02660. vioations charged lepton flavour universality has been the subject sible for t he eff ect ive Higgs Yukaw a couplings (fi g ure 3). S F K ing and C Luhn 2013 Rept. Prog. Phys. 056201. of charged of intense experimental scrutiny over the years and has In such a model the couplings of and/or Z′ S F K ing and G G Ross 2001 Phys. Lett 243. lepton fl avour passed all the tests – until now. In recent years, anoma- bosons may be related to the Higgs Yukawa couplings, J C Pati and A Salam 1974 Phys. Re. 1 275. universality lies have appeared associated with violations of charged c ψi ψj ψi ψj le p t o n fl a v o u r u n i v e r s a l it y i n t h e fi n a l s t at e s a s s o c i at ed w it h t he quark transit ions b → c and b → s.

Puzzle solving In the case of b → c t r a n s it io n s, t h e fi n a l s t at e s i n v ol v i ng YOUR OPTICS, OUR FOCUS φ φ τ leptons appear to violate charged lepton universality. In φ φ (*) At Inrad Optics, we make bent-crystal monochromator applications not just possible—but practical. particular B → D  ν decays where the charged lepton  φ φ φ φ φ φ is identified withτ h a v e b e e n s h o w n b y B a b a r a n d L HC b t o occur at rates somewhat higher than those predicted by Fig. 3. The leptoquark (LQ) or Z′ may couple to quarks and leptons via the same kind t h e S M (t h e r at io s o f s uc h fi n a l s t at e s t o t h o s e i n v ol v ing Thanks to our state-of-the-art optical manufacturing of effective operators as those responsible for the effective Higgs Yukawa couplings. electrons and muons being denoted by R and R ). This is D D* and testing methods, our bent-crystal monochromators q u it e p u z z l i n g s i n c e a l l t h r e e t y p e s o f c h a r g e d le p t o n s a r e ad hoc vacuum alignments to break the family symmetry, predicted to couple to the W boson equally, and the decay are opening new doors in analytical chemistry micro- and potentially greatly simplifies the particle content of is dominated by tree-level W exchange. Any new-physics probes, hot plasma diagnostics, black-lighter imaging – the theory. contribution, such as the exchange of a new charged and more. Grown from high quality crystalline material, Higgs boson, a new W′ or a leptoquark, would have to Compactification compete with tree-level W exchange. However, the most our analyzers are designed to optimize the diffraction Although this approach is currently actively being recent measurements by Belle, reported at the beginning efficiency of your imaging system. considered, it is still unclear to what extent it may shed light of 2019 (CERN Courier May/June 2019 p9), measure R and D • Toroids, ellipsoids, cylinders, and aspheres on the entire flavour problem including all quark and lepton RD* to be closer to the SM prediction. mass hierarchies. Alternative string-theory motivated In the case of b → s t r a n s it io n s, t h e L HC b c ol l a b or at io n • Silicon, germanium, quartz, and KAP crystals id e a s for a d d r e s s i n g t h e fl a v o u r pr ob- and other experiments have reported a number of anom- • Crystal planes oriented to ±2 arc-sec lem are also being developed, includ- alies in B → K(*) +– decays such as the R and R ratios The flavour scale is K K* • High vacuum compatibility, no outgassing ing the idea that flavons can arise from of final states containingμ +μ– versus e+e-, which are meas- very unconstrained the components of extra-dimensional ured deviate from the SM by about 2.5 standard deviations. • Uniform performance from unit to unit gauge fields and that their vacuum Such anomalies, if they persist, may be accounted for by

alignment may be achieved as a con- a new contact operator coupling the four fermions bLsLμLμL 2 sequence of the compactification mechanism. suppressed by a dimensionful coefficient M new, where

Recently, there have been some experimental obser- Mnew ~30 TeV, according to a general operator analysis. vations concerning charged lepton flavour universality This hints that there may be new physics arising from violation which hint that the flavour scale might not be t h e n o n-u n i v e r s a l c o upl i n g s o f le p t o q u a r k a n d /or a n e w associated with the GUT scale, but might instead be just Z′ w h o s e m a s s i s t y pic a l l y a fe w TeV i n ord e r t o g e n e r at e To learn more, visit www.inradoptics.com/products/x-ray-imaging-crystals around the corner at the TeV scale (CERN Courier May/ such an operator (where the 30 TeV scale is reduced to June 2019 p33). Recall that in the SM the charged leptons just a few TeV after mixing angles are taken into account).

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FEATURE KATRIN EXPERIMENT

The Karlsruhe Tritium Neutrino (KATRIN) experiment has begun its seven-year-long programme to determine the A VOYAGE TO THE absolute value of the neutrino mass. HEART OF THE NEUTRINO KATRIN n 11 June 2018, a tense silence filled the large lecture h a l l o f t h e K a rl s r u h e I n s t it ut e o f Te c h n olo g y (K I T) O in Germany. In front of an audience of more than 250 p e o ple, 15 r e d b ut t o n s w e r e pr e s s e d s i mu lt a n e o u s l y b y a panel of senior figures including recent Nobel laureates T a k a a k i K ajit a a n d A r t M c D o n a ld. A t t h e s a m e t i m e, o p e r a- tors in the control room of the Karlsruhe Tritium Neutrino (K AT R IN) e x p e r i m e nt lo w e r e d t h e r e t a rd at io n v olt a g e o f t h e a p p a r at u s s o t h at t h e fi r s t b e t a e le c t r o n s w e r e a ble t o p as into KATRIN’s giant spectrometer vessel. Great applause erupted when the first beta electrons hit the detector. I n t h e l o n g h i s t or y o f m e a s u r i n g t h e t r it iu m b e t a-d e c a y spectrum to determine the neutrino mass, the ensuing weeks of K ATRIN’s first data-tak ing opened a new chap- ter. Everything worked as expected, and KATRIN’s ini- tial measurements have already propelled it into the top r a n k s o f n e ut r i n o e x p e r i m e nt s. T h e a i m o f t h i s u lt r a-h i g h- precision beta-decay spectroscope, more t han 15 years in t h e m a k i n g, i s t o d e t e r m i n e, b y t h e m id-2020 s, t h e a b s olut e mass of the neutrino.

Massive discovery Since the discovery of the oscillation of atmospheric neu- t r i n o s b y t h e Sup e r-K a m io k a n d e e x p e r i m e nt i n 1998, a n d of the flavour transitions of solar neutrinos by the SNO experiment shortly afterwards, it was strongly implied Inner space KATRIN’s main spectrometer, the largest ultra-high-vacuum vessel in the world, contains a dual-layer electrode system comprising 23,000 wires to shield the inner volume from charged particles. that neutrino masses are not zero, but big enough to cause interference between distinct mass eigenstates as a neu- of all three neutrino masses of 0.12 eV at 95% confidence trino mass. The most stringent upper limit is currently the state. However, due to the tiny neutrino mass differences, a trino wavepacket evolves in time. We know now that the within the framework of the standard Lambda cold-dark model-dependent bound set by cosmological data, as already weighted sum is observed. This “average three neutrino flavour states we obser ve in experiments matter (ΛCDM) cosmological model. mentioned, which is valid within the ΛCDM model. A second mass” is formed by the incoherent sum of the squares of the

– νe, νμ a n d ντ – a r e m i x t u r e s o f t h r e e n e ut r i n o m a s s s t at e s. Considerations of “naturalness” lead most theorists to approach is to search for neutrinoless double-beta decay, three neutrino mass eigenstates, which contribute to the Though not massless, neutrinos are exceedingly light. speculate t hat t he exceedingly tiny neutrino masses do not which allows a statement to be made about the size of the electron neutrino according to the PMNS neutrino-mixing P r e v io u s e x p e r i m e nt s d e s i g n e d t o d i r e c t l y m e a s u r e t h e s c a le arise from standard Yukawa couplings to the Higgs boson, neutrino masses but presupposes the Majorana nature of matrix. The super-heavy hydrogen isotope tritium is ideal o f n e ut r i n o m a s s e s i n M a i n z a n d T r oit s k pr o d uc e d a n up p e r as per the other fermions, but are generated by a different neutrinos. The third approach – the one adopted by KATRIN for this purpose because it combines a

l i m it o f 2 eV for t h e n e ut r i n o m a s s – a f a c t or 250,000 t i m e s mass mechanism. Since neutrinos are electrically neutral, – is the direct determination of the neutrino mass from the very low endpoint energy, Eo, o f 18.6 keV Great applause smaller than the mass of the otherwise lightest massive they could be identical to their , making them kinematics of a weak process such as beta decay, which is and a short half-life of 12.3 years with elementary particle, the electron. Nevertheless, neutrino M aj or a n a p a r t ic l e s. V i a t h e s o -c a l le d s e e s a w m e c h a n i s m, t h i s completely model-independent and depends only on the a simple nuclear and atomic structure. erupted when the masses are extremely important for cosmology as well as interesting scenario would require a new and very high particle principle of energy and momentum conservation. first beta electrons for p a r t ic le p h y s ic s. T h e y h a v e a nu m b e r d e n s it y o f a r o u n d mass scale to balance the smallness of the neutrino masses, The direct determination of the neutrino mass relies K ATRIN is born THE AUTHORS 336 cm–3, m a k i n g t h e m t h e m o s t a b u n d a nt p a r t ic le s i n t h e which would be unreachable with present accelerators. on the precise measurement of the shape of the beta elec- Around the turn of the millennium, hit t he detector Guido Drexlin universe besides photons, and therefore play a distinct A s n e ut r i n o o s c i l l at io n s a r i s e d ue t o i nt e r fe r e n c e b e t w e e n tron spectrum near the endpoint, which is governed by motivated by the KIT and r ol e i n t h e for m at io n o f c o s m ic s t r uc t u r e. C o m p a r i n g d at a mass eigenstates, neutrino-oscillation experiments are t he av a i lable phase space (fig ure 1). Th is spec t r a l shape is results, Ernst Otten of the University of Mainz and Vladimir Christian Weinheimer from the Planck satellite together with data from galaxy only able to determine splittings between the squares of altered by the neutrino mass value: the smaller the mass, Lobashev of INR Troitsk proposed a new, much more sensi- University of s u r v e y s (b a r yo n ic a c o u s t ic o s c i l l at io n s) w it h s i mu l at io n s o f the neutrino mass eigenstates. Three experimental ave- t h e s m a l le r t h e s p e c t r a l m o d i fic at io n. O n e w o u ld e x p e c to tive experiment to measure the neutrino mass from tritium Münster. t h e e v olut io n o f s t r uc t u r e y ie ld s a n up p e r l i m it o n t h e s u m nues are currently being pursued to determine the neu- s e e t h r e e m o d i fic at io n s, o n e for e a c h n e ut r i n o m a s s e ign- beta decay. To this end, the best methods from the previous

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FEATURE KATRIN EXPERIMENT FEATURE KATRIN EXPERIMENT

TECHNOLOGY TRANSFER DELIVERS ULTIMATE PRECISION Fig. 2. The KIT Many technologies had to be dual-layer wire electrode system Conversely, the KATRIN KIT detector 70 m-long pushed to the limits of what was for background suppression collaboration has returned its KATRIN setup feasible or even beyond. KATRIN and electric-field shaping, this knowledge and methods to the main spectrometer showing the key became a CERN-recognised extreme vacuum was made community. For example, the stages and pre-spectrometer experiment (RE14) in 2007 and possible by rigorous material ISOLDE high-voltage system components. the collaboration worked with selection and treatment in was calibrated twice with the CERN experts in many areas to addition to non-evaporable getter ppm-accuracy KATRIN voltage achieve this. The KATRIN main technology developed at CERN. dividers, and the magnetic and cryogenic pumping system spectrometer is the largest ultra- KATRIN’s almost 40 m-long chain electrical field calculation and differential pumping system high vacuum vessel in the world, of superconducting magnets with tracking programme KASSIOPEIA with a residual gas in the two large chicanes was put into Precise The electron transport developed by KATRIN was tritium source rear range of 10–11 mbar – a pressure operation with the help of former and tritium retention system. published as open source and has system that is otherwise only found in CERN experts, and a 223Ra source become the standard for low- large volumes inside the LHC was produced at ISOLDE for initially produced at ISOLDE. energy precision experiments. ring – equivalent to the pressure background studies at KATRIN. A At present these are produced The fast and precise laser Raman recorded at the lunar surface. series of 83mKr conversion electron by KATRIN collaborators and spectroscopy developed for magnetic-field compensation coils Even though the inner surface sources based on implanted 83Rb further developed with regard to KATRIN is also being applied to was instrumented with a complex for calibration purposes was line stability. fusion technology. KIT

10 mV scale at 18.6 kV. The experiment’s two most impor- KATRIN data with 1σ error bars × 50 10 1 tant and also most complex components are the gaseous, 10 fit result 8 6 windowless molecular tritium source (WGTS) and the very mν = 0 eV 6 large spectrometer. In the WGTS, tritium gas is introduced 0 4 in the midpoint of the 10 m-lo n g b e a m t u b e, w h e r e it flo w s 10 4 count rate (cps) out to both sides to be pumped out again by turbomolecular 2⋅10–13 2 2 ~ pumps. After being partially cleaned it is re-injected, yield-

count rate (arbitrary units) m = 1 eV 2 stat. count rate (arbitrary units) ν ing a closed tritium cycle. This results in an almost opaque stat. and syst. 0 0 column density with a total decay rate of 1011 per second. 0 0 5 10 15 –3 –2 –1 0 The beta electrons are guided adiabatically to a tandem of

residuals ( σ ) 2 E (keV) E–E0 (eV) a pre- and a main spectrometer by superconducting mag- 18535 18555 18575 18595 18615 n e t s o f up t o 6 T. A lo n g t h e w a y, d i ffe r e nt i a l a n d c r yo g e n ic retarding energy (eV) Fig. 1. The beta experiments in Mainz, Troitsk and Los Alamos were to be pumping sections including geometric chicanes reduce the Focus Operators in the KATRIN control room. spectrum of combined and upscaled by up to two orders of magnitude tritium flow by more t han 14 orders of mag nitude to keep tritium (left), in size and precision. Together with new technologies and t he spect rometers free of t rit ium (fig ure 2). complex calibration and monitoring system to determine very well (figure 3) and the fitted endpoint turned out to Fig. 3. The showing in detail ideas, such as laser Raman spectroscopy or active back- all systematics with the highest precision in situ, e.g. the be compatible wit h t he mass difference bet ween 3He and beta-electron the effect of ground reduction methods, the apparatus would increase Filtration source strength, the inelastic scattering of beta electrons tritium measured in Penning traps. The new results were spectrum in the different neutrino the sensitivity to the observable in beta decay (the square of The KATRIN spectrometers operate as so-called MAC-E in the tritium source, the retardation voltage and the work presented at the international TAUP 2019 conference in vicinity of its masses on the the electron antineutrino mass) by a factor of 100, resulting filters, whereby electrons are guided by two supercon- functions of the tritium source and the main spectrometer. Toyama, Japan, and have recently been published. endpoint with endpoint (right). in a neutrino-mass sensitivity of 0.2 eV. Accordingly, the ducting solenoids at either end and their momenta are This first result shows that all aspects of the KATRIN 50 times enlarged entire experiment was designed to the limits of what was c ol l i m at e d b y t h e m a g n e t ic fie ld g r a d ie nt. T h i s “m a g n e t ic Start-up and beyond experiment, from hardware to data-acquisition to analysis, error bars and a feasible and even beyond (see “Technology transfer delivers bottle” effect transforms almost all kinetic energy into After intense periods of commissioning during 2018, the works as expected. The statistical uncertainty of the first best-fit model ultimate precision” box). longitudinal energy, which is filtered by an electrostatic tritium source activity was increased from its initial value KATRIN result is already smaller by a factor of two compared (top) and fit KIT was soon identified as the best place for such an retardation potential so that only electrons with enough of 0.5 GBq (which was used for the inauguration measure- to previous experiments and systematic uncertainties have residuals (bottom). experiment, as it had the necessary experience and infra- energy to overcome the barrier are able to pass through. ments) to 25 GBq (approximately 22% of nominal activity) gone down by a factor of six. A neutrino mass was not yet structure with the Tritium Laboratory Karlsruhe. The KIT The smaller pre-spectrometer blocks the low-energy part i n s pr i n g 2019. B y A pr i l, t he fi r s t K AT R IN s c ie nc e r u n h a d e x t r a c t e d w it h t h e s e fi r s t fo u r w e e k s o f d at a, b ut a n upper board of directors quickly took up this proposal and a small of the beta spectrum (which carries no information on the begun and everything went like clockwork. The deci- l i m it for t h e n e ut r i n o m a s s o f 1.1 eV (90% confidence) can be international working group started to develop the pro- neutrino mass), while the 10 m-diameter main spectrometer sive source parameters – temperature, inlet pressure and d r a w n, c at a p u lt i n g K AT R IN d i r e c t l y t o t h e t o p o f t h e w orld ject. At a workshop at Bad Liebenzell in the Black Forest in provides a much sharper filter width due to its huge size. tritium content – allowed excellent data to be taken, and of direct neutrino-mass experiments. In the mass region January 2001, the project received so much international The transmitted electrons are detected by a high-resolution the collaboration worked in several independent teams to around 1 eV, the limit corresponds to the quasi-degenerated support that KIT, together with nearly all the groups from segmented silicon detector. By varying the retarding poten- analyse these data. The critical systematic uncertainties neutrino-mass range where the mass splittings implied by the previous neutrino-mass experiments, founded the tial of the main spectrometer, a narrow region of the beta were determined both by Monte Carlo propagation and neutrino-oscillation experiments are negligible compared KATRIN collaboration. Currently, the 150-strong KATRIN spectrum of several tens of eV below the endpoint is scanned, with the covariance-matrix method, and the analyses to the absolute masses. collaboration comprises 20 institutes from six countries. where the imprint of a non-zero neutrino mass is maximal. were also blinded so as not to generate bias. The excite- T h e n e ut r i n o -m a s s r e s u lt f r o m K AT R IN i s c o m ple m e nt a r y It t o o k a l m o s t 16 y e a r s f r o m t h e fi r s t d e s i g n t o c o m pl e te Since the relative fraction of the tritium beta spectrum in the ment during the un-blinding process was huge within to results obtained from searches for neutrinoless double beta –13 KATRIN, largely because many new technologies had to be last 1 eV below the endpoints amounts to just 2 × 10 , KATRIN t h e K AT R IN c ol l a b or at io n, w h ic h g at h e r e d for t h i s s p e c i a l decay, which are sensitive to the “coherent sum” mββ of all developed, such as a novel concept to limit the temperature demands a tritium source of the highest intensity. Of equal event, and relief spread when the result became known. The neutrino mass eigenstates contributing to the electron neu- fluctuations of the huge tritium source to the mK scale at importance is the high precision needed to understand the neutrino-mass square turned out to be compatible with trino. Apart from additional phases that can lead to possible 30 K or the high-voltage stabilisation and calibration to the measured beta spectrum. Therefore, KATRIN possesses a zero within its uncertainty budget. The model fits the data cancellations in this sum, the values of the nuclear matrix

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FEATURE ATRI EERIET FEATURE OUTREACH

elements that need to be calculated to connect the neutrino neutrino-mass eperiments of about 10 meV (0 meV) for

mass mββ with the observable (the half-life) still possess normal (inverse) mass ordering. Therefore, many plans eist uncertainties of a factor two. Therefore, the result from a to cover this region in the future. At KATRIN, there is a strong direct neutrino-mass determination is more closely con- R&D programme to upgrade the MAC-E fi lter principle from Tactile Collider nected to results from cosmological data, which give (model- the current integral to a diff erential read-out, which will dependent) access to the neutrino-mass sum. allow a factor-of-two improvement in sensitivity on the neutrino mass. New approaches to determine the absolute A sizeable infl uence neutrino-mass scale are also being developed: Project , a Currently, KATRIN is taking more data and has already radio-spectroscopy method to eventually be applied to an increased the source activity by a factor of four to close to atomic tritium source and the electron-capture eperi- its design value. The background rate is still a challenge. ments ECHo and HLES, which intend to deploy large Hands-on Various measures, such as out-baking and using liuid-nitro- arrays of cryogenic bolometers with the implanted isotope 3D models of bar gen cooled baffl es in front of the getter pumps, have already 13Ho. In parallel, the net generation of neutrinoless double magnets with yielded a background reduction by a factor 10, and more will beta decay eperiments like LEGEN, CUPI or nE (as tactile bumps for north and south A n upp er b e i m ple m e nt e d i n t h e n e x t fe w y e a r s. For t h e fi n a l K AT R IN well as future enon-based dark-matter eperiments) aim poles help convey l i m it for t he sensitivity of 0.2 eV (90% confi dence) on the absolute neu- to cover the full range of inverted neutrino-mass ordering. trino-mass scale, a total of 1000 days of data are reuired. F i n a l l y, r e fi n e d c o s m olo g ic a l d at a s h o u ld a l lo w u s t o pr o b e the principles neutrino mass With this sensitivity KATRIN will either fi nd the neutrino the same mass region (and beyond) within the net decades, of particle of 1.1 eV can mass or will set a stringent upper limit. The former would while long-baseline neutrino-oscillation eperiments, accelerators. b e d r aw n, confront standard cosmology, while the latter would eclude such as UN, UNE and Hyper-Kamiokande, will probe catapulting quasi-degenerate neutrino masses and a sizeable infl uence the neutrino-mass ordering implemented in nature. As a ATRI of neutrinos on the formation of structure in the universe. result of this broad programme for the 2020s, the elusive directly to This will be augmented by searches for physics beyond the neutrino should fi nally yield some of its secrets and inner t he top of t he Standard odel, such as for admitures properties beyond miing.  world of d i r e c t with masses from the eV to the keV scale. neutrino-mass Neutrino-oscillation results yield a lower limit for the Further reading experiments eff ective electron-neutrino mass to manifest in direct KATRIN Collaboration 201 hys. ev. ett. 22102. ENGAGING WITH 300kW All Solid-State RF Amplifier Model : CA500BW2-8085RP R&K Company Limited R&K provides the world’s most reliable high performance solid-state RF Power Amplifiers. THE INVISIBLE AMPLIFIER DESIGN ・Consists of four (4) rack-mounted 75kW SSAs. The outreach project Tactile Collider is changing the way particle physicists engage ・Able to deliver 300kW via 4-way power combiner. ・96-way radial combiner for final power combining with visually impaired and other important audiences, writes founder Rob Appleby. of 75kW SSA. ・Long-term & highly reliable operation achieved by protecting each final-stage transistor with e have many fantastic achievements in our on or read a newspaper article about medical built-in circulator at its output. wonderful field of research, most recently the accelerators – is a vital part of our work, and we do it well. 96-way Radial Combiner completion of the (LHC) But many audiences have barriers to traditional modes of Output Power Linearity ■Output Pulse 86 Frequency = 500MHz, Po = 300kW 85 W X：50μs / DIV Y：200mV / DIV 84 FWD LIMIT and its discovery of a new form of matter, the Higgs boson. o ut r e a c h a n d e n g a g e m e nt. For e x a m ple, g r o up s or f a m i l ie s 83 82 81 80 T h e fie ld i s n o w pr e p a r i n g t o f a c e t h e n e x t s e t o f c h allenges, with an inherently low science background, perhaps linked 79 78 77 76 in whatever direction the European Strategy for Particle to socio-economic grouping, will not read articles in the 75 74 73 72 Physics recommends. With ambitious goals, this strategy science-literate mainstream press as they feel, incorrectly,

Output Power (dBm) 71 Frequency 70 69 499MHz update is the right time to ask: “How do we make ourselves that science is not for them. Large potential audiences with 68 500MHz 67 501MHz -15 -10 -5 0 5 10 as good as we need to be to succeed?” physical or mental disabilities will be put off coming to Input Power (dBm)

■Pulse Rise ■Pulse Fall Big science has brought more than fundamental knowl- events for practical reasons such as accessibility or per- Frequency = 500MHz, Po = 300kW Frequency = 500MHz, Po = 300kW X：200ns / DIV Y：200mV / DIV X：50ns / DIV Y：200mV / DIV SPECIFICATION edge: it has taught us that we can achieve more when we haps being unable to read or understand printed or visual collaborate, and to do this we need to communicate both media. In the UK alone, millions of people are registered as Frequency Range : 500MHz±1MHz Output Power : 320kW @Peak, 300kW (min.) within and beyond the community. We need to communi- visually impaired (VI) to some degree. To reach these and *Each rack-mounted amplifier section individually delivers 75kW. cate to our funders and, most importantly of all, we need other “invisible” audiences, we need to enter their space. (75kW/rack ×4 outputs) to communicate with wider society to give everyone an ～ THE AUTHOR Pulse Width : 1μs 300μs (max.) o p p or t u n it y t o e n g a g e i n or b e c o m e a p a r t o f t h e s c ie nt i fic Inspired by the LHC Duty : 0～3% (max.) Rob Appleby process. Yet some of the audiences we could and should be When it comes to science engagement, which is a pre- R&K Company Limited Operation Mode : Class AB University of www.rk-microwave.com AC Supply Input : AC200V±10%／3φ, 50／60Hz reaching are below the . dominantly visual interaction, the VI audience is under- Manchester and 721-1 Maeda, Fuji-City, Shizuoka, 416-8577 Japan Size : (W)2240mm×(D)1300mm×(H)1510mm Reaching high-science capital people – those who will served. Tactile Collider is a communication project aimed the Cockcroft Tel:+81-545-31-2600 Fax:+81-545-31-1600 Email:[email protected] attend a laboratory open day, watch a new documentary at addressing this gap. The idea came in 2014 when a major Institute, UK

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FEATURE OUTREACH FEATURE OUTREACH

Tactile Collider toured the UK in 201 and 201, visiting Eyres S many mainstream and specialist schools, and meeting many motivated and enthusiastic students. We have also Tactile Collider spent time at music festivals, with a focus on raising aware- ness of VI issues and giving people a chance to learn about the LHC using senses other than their eyes. ne legacy of Tactile Collider is educating our community, and we are planning “VI in science” training events in 2020 in addition to a third community meeting bringing together scientists and communication professionals. There is now a real interest and understanding in particle physics about the importance of reaching under- represented audiences. Tactile Collider is a step towards this, and we are working to share the skills and insights we have gained in our journey so far. The idea has also appeared in astronomy: Tactile Universe, based at the Institute of Cosmology and at the University of Portsmouth, engages the VI community with astrophysics research, for eample by creating 3 printed tactile images innin orla actile Colliders Chris dmonds, ob ppleby and obyn atson of galaies for use in schools and at public events. The left to right with the uropean hysical ociety utreach ward in uly . fi r s t j oi nt T a c t i le C ol l id e r/ Un i v e r s e e v e nt w i l l t a k e pl a c e The team also won Innovator of the Year in the 2019 RNIB See Diff erently awards. in in 2020 and we have already jointly hosted In the field LHC exhibition came to Manchester, UK. Joining in panel a c c e le r ate t he s e p a r t ic le s u s i n g e le c t r ic fie ld s i n c a v it ie s; two community workshops. The Tactile Collider team is endeavour. When we consider the Higgs boson and super- Interactive magnet discussions at a launch party held at the Museum for we control particle beams using magnets; and we collide happy to discuss bringing the ehibition to any event, novae, none of us can directly engage with the very small exhibits on display Science and Industry, it became clear that the accessibility particle beams to make the Higgs boson. The first sig- lab or venue. or the far or the very massive. Using all of our senses shows at Tactile Collider. of the exhibition could be improved. Spurring us into action, nificant event took place in Liverpool in 2017 and since undamental science is a humbling and levelling us science inCryogenFreeProbe#2-CERN a new and fascinating way. 9/21/13 2:58 PM Page 1 we also had a request from a local VI couple for an adapted then the exhibition has toured UK schools, science festi- tour. I gathered together some pieces of the ATLAS forward vals and, in 2019, joined the CERN Open Days for our first detector and some radio-frequency cavity models, both Geneva-region event. of which had a pleasing and plenty of features to feel with fingers, and gave the couple a bespoke tour of Content development the exhibition. The feedback was fantastic, and making A ke y a s p e c t of T ac t i le C ol l ide r i s c onte nt de ve lop e d s p e- this tactile, interactive and bespoke form of engagement c i fic a l l y for a V I a ud ie n c e, a lo n g w it h t r a i n i n g t h e d e livery available to more people, be it sighted or VI, was a chal- team in how to sight-guide and educating them about the Cryogen lenge we accepted. l a r g e r a n g e o f v i s u a l i m p a i r m e nt s. A s a n e x a m ple, t a k e t h e With the help of the museum staff, we developed the m a g n e t ic fie ld o f a d i p ole – t h e fi r s t s t e p t o u n d e rstandig Free Probe idea further and were soon put in touch with Kirin Saeed, how magnets are used to control and manipulate charged an independent consultant on accessibility and visually particle beams. The idea of a bar magnet having a north Bright, Stations impaired herself. Together, we formulated a potential pro- pole and a south pole, and magnetic field lines connect- ject to a stage where we could approach funders. The UK’s ing the two, is simple enough to convey using pencil and Dense, Fast Science and Technology Facilities Council (STFC) recog- paper. To communicate with VI audiences, by contrast, Crystals for your nised and supported our for a UK-wide project and the magnet station of Tactile Collider contains a 3D model Applications include funded the nascent Tactile Collider for two years through of a bar magnet with tactile bumps for north and south World-Class Research nano science, materials and spintronics a £100,000 public-engagement grant. poles, partnered with tactile diagrams. In some areas of State-of-the-art scintillation & detection solutions We wanted to design a project without preconceptions Tactile Collider, 3D sound is employed to give students a <5 K - 675 K cryocooler- Crystals: Grown to spec within short lead times about the techniques and methods of communication and choice in how to interact. based systems delivery. With co-leaders Chris Edmonds of the University The lessons learned during the project’s development and Arrays: Linear and 2D from 5mm to 200mm Vibration isolated for of Liverpool and Robyn Watson, a teacher of VI students, delivery led us to a set of principles for engagement, which Detectors: Single units and complete assemblies sub-micron sample stability our team spent one year listening to and talking with work for all audiences regardless of any particular needs. (PMT, CCD, and SiPM) Up to 8 probes, DC to 67 GHz, plus fiber optics audiences before we even considered producing mat- We found that all science engagement should strive to be Zoom optics with camera and monitor CLLBC CLYC erials or defining an approach. We spent time in focus authentic, with no dumbing down of the science message Materials BGO CaF2 (Eu) GLuGAG Horizontal, vertical or vector magnetic field groups, in classrooms across the north of England, vis- and delivered by practicing scientists striving to involve the Index Csl Csl(Tl) Csl(Na) LYSO Nal Nal(Tl) options are available it i ng museums w it h V I people, a nd look i ng at t he v a r ied audience as equals. Alongside this authentic message, VI None of us Other configurations: LHe, LN , room temperature ways of learning and accessing information for VI groups learners require close interaction with a scientist-presenter 2 and UHV systems can directly of all ages. Training in skills such as audio description in a group of no bigger than four. The scientist should also CONTACT US TODAY: Mention Contact us today: engage with and tactile-map production was crucial, as were the PhD be trained in VI-audience awareness, sighted guiding, audio [email protected] CERN20 [email protected] the very small students who got involved to design materials and deliver description and in the presentation of a tactile narrative +44 1843 231166 for free www.janis.com /CryogenFreeProbeStation.aspx or the far Tactile Collider events. linked to the learning outcomes. Coupled with this idea is hilger.dynasil.com shipping www.facebook.com /JanisResearch or the very Early on, we focused on a science message based around t h e n e e d t o t r a i n pr e s e nt e r s t o b e a ble t o u s e t h e d i ffe r i n g massive four key themes: the universe is made of particles; we materials with diverse audience groups.

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Subjects include: • Instrumentation and hardware for accelerators Learning to love anomalies Detectors, apparatus and methods for particle, astroparticle, nuclear and

• iStock/voyata molecular physics The 2020s will sort current anomalies in • Instrumentation and techniques for dosimetry, monitoring and radiation damage fundamental physics into discoveries or phantoms, says Ben Allanach. 2019 Special Issues include: Landmark LHC Technical Reports – scientific documentation on the CERN Large • Anomalies, which I take to mean data Hadron Collider that disagree with the scientific para- • Tevatron Accelerator Special Issue – work by the Tevatron team in the field of digm of the day, are the bread and butter beam physics and accelerator technology o f p h e n o m e n ol o g i s t s w or k i n g o n p h y s- ics beyond the Standard Model (SM). Are they a mere blip or the first sign of new To find out more about submitting, please visitiopscience.org/jinst physics? A keen understanding of sta- or e-mail [email protected] t i s t i c s i s n e c e s s a r y t o h e l p d e c i d e w h i c h Outliers All surprising discoveries were anomalies at some stage. “bumps” to work on. Ben Allanach Take the excess in the rate of di- proved to contribute much more than was When working on an anomaly, beyond- Created jointly by the International School is a theorist at photon production at a mass of around previously thought, faithfully describ- the-SM phenomenologists hypothesise a of Advanced Studies and IOP Publishing. the University 750 G eV s p o t t e d i n 2015 b y t h e AT L A S a n d ing top–antitop production both at the n e w p a r t i c l e a n d /or i nt e r a c t i o n t o e x pl a i n of Cambridge C M S e x p e r i m e nt s. AT L A S h a d a 4 σ p e a k Tev at ron and at t he LHC. it, check to see if it works quantitatively, working on the w it h r e s p e c t t o b a c k g r o u n d, w h i c h C M S Other anomalies are still alive and check to see if any other measurements phenomenology seemed to confirm, although its signal kicking. Arguably, chief among them is rule the explanation out, then provide of physics beyond was less clear. Theorists produced an the long-standing oddity in the measure- new ways in which the idea can be tested. the Standard Model. a v a l a n c h e o f p a p e r s s p e c u l a t i n g o n w h a t ment of the anomalous magnetic moment After this, they usually check where the the signal might mean but, in the end, the of the muon, which is about 4σ discrepant new physics might fit into a larger the- signal was not confirmed in new data. w it h t h e S M pr e d i c t i o n s. S p o t t e d 20 y e a r s oretical structure, which might explain Before the Internet of Space In f ac t, a s i s s o of te n t he c a s e, t he put a- ago, many papers have been written in an some other mysteries. For example, tive signal stimulated some very fruitful a t t e m p t t o e x pl a i n it, w it h c o nt r i b ut io n s there are currently many anomalies in work. For example, it was realised that ranging from supersymmetric particles measurements of decays, each can revolutionize data ultra-peripheral collisions between to leptoquarks. A similarly long-standing of which isn’t particularly statistically lead ions could produce photon-photon anomaly is a 3.8σ excess in the number s i g n i fic a nt (t y pi c a l l y 2-3 σ away from the sharing, antenna designs resonances, leading to an innovative of electron antineutrinos emerging from SM) but taken together they form a coher- and unexpected search programme in a muon–antineutrino beam observed by e nt pi c t u r e w it h a h i g h e r s i g n i fic a n c e. T h e heav y-ion physics. Other authors pro- t h e L SN D e x p e r i m e nt a n d b a c k e d up m or e e x c h a n g e o f h y p o t h e s i s e d Z′ or l e p t o q u a r k must be optimized. posed using such collisions to measure recently by MiniBooNE. Again, numerous quanta provide working explanations, the the anomalous magnetic moment of papers attempting to explain the excess, larger structure also shedding light on the tau lepton, which is expected to be e.g. in terms of the existence of a fourth the pattern of masses of SM fermions, The wired and wireless networks that currently connect especially sensitive to new physics, and “sterile” neutrino, have been written, and most of my research time is currently people around the world cannot reach everywhere on in 2018 ATLAS and CMS found the first but the jury is still out. devoted to studying them. Earth. To solve the problem, engineers are turning their evidence for (non-anomalous) high- Some anomalies are more recent, The coming decade will presuma- energy light-by-light scattering in lead- and unexpected. The so-called “X17” bly sort several current anomalies into eyes toward space. The goal is to form a suborbital high- lead ultra-peripheral collisions. anomaly reported at a nuclear physics discoveries, or those that “went away”. data-rate communications network to revolutionize Some anomalies have disappeared experiment in Hungary, for instance, Bel le II a nd f ut ure LHCb measurement s how data is shared and collected. In order to build a during the past decade not primarily shows a significant excess in the rate should settle the B anomalies, while the functioning Internet of Space, design engineers need to because they were statistical fluctua- of certain nuclear decays of 8Be and 4He anomalous muon magnetic moment may optimize their antenna designs. t io n s, b ut b e c a u s e o f a n i m pr o v e d u n d e r- nuclei (see p7) which has been interpreted even be settled this year by the g-2 exper- standing of theory. One example is the as being due to the creation of a new iment at Fermilab. Of course, we hope

The COMSOL Multiphysics® software is used for forward-backward asymmetry (AFB) of p a r t i c l e o f m a s s 17 MeV. Though possible t h a t n e w a n o m a l i e s w i l l a p p e a r a n d s t i c k . simulating designs, devices, and processes in all fields of t o p –a nt it o p pr o d u c t io n a t t h e Te v a t r o n. theoretically, one needs to work hard to One anomaly from the late 1990s – that At large transverse momentum, A was make this new particle not fall afoul of type 1a supernovae have an anomalous engineering, manufacturing, and scientific research. See Of course, FB how you can apply it to advanced antenna designs. we hope measured to be much too large compared other experimental constraints; con- a c c e l e r a t io n a t l a r g e r e d-s h i f t s – t u r n e d t o S M pr e d i c t i o n s, w h i c h w e r e a t n e x t-t o - firmation from an independent exper- out to reveal the existence of dark-energy Visualization of the electric that new field, power flow, and sharp leading order in QCD with some partial iment is also needed. Personally, I am and produce the dominant paradigm of comsol.blog/IoS anomalies far-field radiation pattern of a next-to-next-to leading order (NNLO) not pursuing this: I think that the best cosmology today. This reminds us that parabolic reflector antenna. will appear c or r e c t i o n s. T h e c o m pl e t e N N L O c or r e c- n e w-p h y s ic s id e a s h a v e a l r e a d y b e e n h a d a l l s u r pr i s i n g d i s c o v e r i e s w e r e a n o m a l i e s and stick tions, calculated in a Herculean effort, by other authors. at some stage.

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Services OPINION High-end test & measurement services (Analog/Digital Signal Integrity, up to 20 GHz) Hardware, firmware & software development INTERVIEW Timing systems Consulting & integration Trainings (basic and advanced) Turn Key Systems The Higgs, supersymmetry and all that We speak Low Level RF Controls GigE Vision image processing systems Industrial test automation & quality control John Ellis reflects on 50 years spent working at the forefront of theoretical high-energy physics MicroTCA MicroTCA Training a nd w he t her t he fie ld i s r ip e for a c h a nge of pa r ad igm. Basic building blocks & components J Ordan/CERN What would you say were the best System assembly & configuration and the worst of times in your half- System management (incl. MCH and IPMI) century-long career as a theorist? Come Communication protocols The two best times, in chronological (e.g. PCI Express, Gigabit Ethernet) order, were the 1979 discovery of the Timing, triggers & interlocks gluon in three-jet events at DESY, Support for development in MicroTCA which Mary Gaillard, Graham Ross talk to us and I had proposed three years earlier, Troubleshooting procedures and the discovery of the Higgs boson at CERN in 2012, in particular because one of the most distinctive signatures Tel. +49 (0) 40 8998 1887 for the Higgs, its decay to two photons, Registration & details: [email protected] was something Gaillard, Dimitri techlab.desy.de/services/training techlab.desy.de Nanopoulos and I had calculated in 1975. There was a big build up to the Higgs and it was a really emotional moment. The first of the two worst times was in 2000 with the closure of LEP, because maybe there was a glimpse of the Higgs boson. In fact, in retrospect the decision was correct because the Higgs wasn’t there. The Deep thought John Ellis of King’s College London in his office at CERN in July 2019. other time was in September 2008 IOP Expanding Physics IOP Expanding Physics IOP Expanding Physics IOP Expanding Physics when there was the electrical accident of morally convinced beforehand that of the Higgs potential in the SM goes Experimental Energy Density A Modern Course in A Modern Course in Particle Physics Functional Methods Quantum Field Theory Quantum Field Theory Editor’s picks in the LHC soon after it started up. the Higgs had to exist, but by the early negative if you extrapolate it to high Understanding the measurements and for Atomic Nuclei Fundamentals Advanced topics searches at the Large Hadron Collider No theoretical missing factor-of-two 1990s it was clear that, indirectly, we energies, the theory becomes unstable Edited by Badis Ydri Badis Ydri Deepak Kar Nicolas Schunck of 2019 in could be so tragic. had seen it. Before that there were and the universe is doomed. And, in VOLUME VOLUME ONE TWO alternative models of electroweak principle, you can add a constant term quantum and Your 1975 work on the phenomenology symmetry breaking but LEP killed to the Higgs potential, which is the of the Higgs boson was the starting most of them off. infamous cosmological constant that particle physics point for the Higgs hunt. When did we know exists in the universe today you realise that the particle was more To what extent does the Higgs boson but that is much, much smaller than likely than not to exist? represent a “portal” to new physics? would seem natural from the point Visit iopscience.org/books Our paper, published in 1976, helped The Higgs boson is often presented as of view of Higgs theory. Presumably people think about how to look for the completing the Standard Model (SM) some new physics comes in to fi x t hese IOP Concise Physics A Morgan & Claypool Publication IOP Concise Physics A Morgan & Claypool Publication IOP Concise Physics A Morgan & Claypool Publication IOP Concise Physics A Morgan & Claypool Publication for more information, a full Particle Physics International Linear B Factories The Physics Higgs boson, but it didn’t move to the and solving lots of problems. Actually, problems, and that makes the Higgs list of titles and to learn top of the physics agenda until after it opens up a whole bunch of new ones. sector of the SM Lagrangian look like Richard A Dunlap Collider (ILC) Boštjan Golob of Emergence The next mega-scale particle collider Robert C Bishop the discovery of the We know now that there is at least one the obvious portal to that new physics. Alexey Drutskoy why you should become an in 1983. When we wrote the paper, par t icle t hat looks li ke an effect ive IOP ebook author. things like spontaneous symmetry elementary scalar field. It’s an entirely In what sense do you feel an breaking were regarded as speculative new type of object that we’ve never emotional connection to theory? hypotheses by the distinguished encountered before, and every single The Higgs discovery is testament to grey-haired scientists of the day. aspect of the Higgs is problematic from Every single the power of mathematics to describe Then, in the early 1990s, precision a theoretical point of view. Its mass: aspect of nature. People often talk about beauty measurements at LEP enabled us we know that in the SM it is subject to the Higgs is as being a guide to theory, but I am to look at the radiative corrections quadratic corrections that make the problematic always a bit sceptical about that induced by the Higgs and they painted hierarchy of mass scales unstable. Its because it depends on how you define a consistent picture that suggested couplings to fermions: those are what from a beauty. For me, a piece of engineering the Higgs would be relatively light produce the mixing of quarks, which is theoretical can be beautiful even if it looks ugly. (less than about 300 GeV). I was sort a complete mystery. The quartic term point of view The LHC is a beautiful machine from

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OPINION INTERVIEW OPINION INTERVIEW

that point of view, and the SM is a We are never going to know that the couplings of these particles, regard that as a bit unfair, but there are theory that works fantastically well beautiful theoretical machine that is The discover y of g rav it at iona l SUSY is not there. String theorists and it’s not clear to me that in these always fashions in . but leaves many mysteries – such driven by mathematics. At the end of could probably live with very heavy eff ect ive-SUSY systems one can tal k as dark matter, the origin of matter, the day, mathematics is nothing but w aves a lmost four years SUSY particles. When I first started in a meaning f ul w ay about what t he ollowing a long and highly successful neutrino masses, cosmological logic taken as far as you can. ago w as t he “Higgs moment” thinking about SUSY in the 1980s there couplings look like. period of theory-led research, infl ation, etc – still standing. was this motivation related to fine culminating in the completion of the These are a mi x t ure of t heoret ical, Do you recall the moment you first for gravity tuning, but there weren’t many other Has the H new-physics no-show so SM, what signposts does theor y off er phenomenological and experimental encountered supersymmetry (SUSY), reasons why SUSY should show up at far impacted what theorists work on? experimentalists from here? problems suggesting life beyond and what convinced you of its potential? low energies. More arguments came In general, I think that members I would broaden your question. In the SM. But we don’t have any clear I guess it must have been around 1980. of how much resistance to pain you later, for example, dark matter, which of the theoretical community particle physics, yes, we have the SM, signposts today. The theoretical cats Of course I knew that Julius Wess and have. That said, to my mind the LHC are nice but a matter of taste. I and have diversifi ed their interests whic h over t he past 50 years has been are w andering off in all direct ions, and Bruno Zumino had discovered SUSY has actually provided three additional my grandchildren will have passed and are t hin k ing about alter nat ive t he dominant paradig m. But t here t hat’s good because maybe one of t he as a theoretical framework, but their reasons for loving SUSY. One is the on, humans could still be exploring dark-matter scenarios, and about is also a paradigm in cosmology and cats will fi nd something interesting. motivations didn’t convince me. Then correct prediction for the Higgs mass. physics way below the Planck scale, alter nat ive w ays to stabilise t he gravitation – and the But t here is st ill a dialog ue going on people like Luciano Maiani, Ed Witten Another is that SUSY stabilises the and string theorists could still be cool hierarchy problem. People are idea of a big bang – initiated a century between theory and experiment, and and others pointed out that SUSY electroweak vacuum (without it, SM with that. certainly exploring new theoretical ago by Einstein. The 2016 discovery it’s a dialogue that is maybe less of could help stabilise the hierarchy of calculations show that the vacuum is avenues, which is very healthy and, of gravitational waves almost four a monologue than it was during the mass scales that we find in physics, metastable). The third is that in a SUSY How high do the masses of the super- in a way, there is much more freedom years ago was the “Higgs moment” for rise of the SM and general relativity. such as the electroweak, Planck and model, the Higgs couplings to other partners need to go before SUSY ceases for young theorists today than gravity, and that community now fi nds The problems we face in going grand unification scales. For me, the particles, while not exactly the same as to offer a compelling solution for the there might have been in the past. itsel f in t he same fi x t hat we do, in t hat beyond the current paradigms in first phenomenological indication in the SM, should be pretty close – and hierarchy problem and dark matter? Personally, I would be rather reluctant t hey have t his t heor y-led paradig m f undamental physics are t he hardest that indicated SUSY could be related of course that’s consistent with what Beyond about 10 TeV it is difficult to at this time to propose to a PhD t hat doesn’t indicate where to go ne x t. we’ve faced yet, and we are going to to reality was our realisation in 1983 has been measured so far. see how it can provide the dark matter student a thesis that was based solely Gravitational waves are going to tell us need all the dialogue we can muster that SUSY offered a great candidate unless you change the early expansion on SUSY – the people who are hiring a lot about astrophysics, but whether between theorists, experimentalists, for dark matter in the form of the To what extent is SUSY driving history of the universe – which of are quite likely to want them to be not they will tell us about quantum gravity astrophysicists and cosmologists. lightest supersymmetric particle. The considerations for the next collider? course is quite possible, because we just working on SUSY and maybe even is not so obvious. The Higgs boson, second was a few years later when LEP I still think it’s a relatively clear-cut have no idea what the universe was not working on SUSY at all. I would meanwhile, tells us that we have a nterview by ahe hale editor. provided very precise measurements and well-motivated scenario for doing when the temperature was of the electroweak mixing angle, physics at the multi-TeV scale. But above an MeV. Indeed, many of my which were in perfect agreement obviously its importance is less than string colleagues have been arguing with supersymmetric (but not non- it was in the early 1990s when we were that the expansion history could be POWERED BY supersymmetric) grand unified proposing the LHC. That said, if you rat her different from t he convent ional theories. The third indication was want a specific benchmark scenario for adiabatic smooth expansion that around 1991 when we calculated the new physics at a future collider, SUSY people tend to use as the default. In mass of the lightest supersymmetric would still be my go-to model, because this case supersymmetric particles Higgs boson and got a mass up to about you can calculate accurate predictions. could weigh 10 or even 30 TeV and still 130 GeV, which was being indicated As for new physics beyond the Higgs provide the dark matter. As for the by LEP as a very plausible value, and and more generally the precision hierarchy problem, obviously things agrees with the experimental value. measurements that you can make in get tougher to bear. The World’s Most Advanced the electroweak sector, the next topic Digital Pulse Processor There was great excitement about that comes to my mind is dark matter. What can we infer about SUSY as a SUSY ahead of the LHC start-up. In If dark matter is made of weakly- theory of fundamental particles from for high-rate Spectroscopy hindsight, does the non-discovery so interacting massive particles (WIMPs), its recent “avatars” in lasers and far make the idea less likely? a high-energy condensed-matter systems? Certainly it’s disappointing. And I have should be able to discover it. You I don’t know. It’s not really clear to me • Up to 8 channels to face the possibility that even if SUSY can look at SUSY at various different that the word “SUSY” is being used of simultaneous is there, I might not live to meet her. But levels. One is that you just add in in the same sense that I would use it. processing I don’t think it’s necessarily a problem these new particles and make sure Supersymmetric quantum mechanics for the underlying theory. There are t hey have t he right couplings to fi x was taken as a motivation for the • Over 3 Mcps certainly scenarios that can provide the the hierarchy problem. But at a more laser setup (CERN Courier March/April processed by dark matter even if the supersymmetric fundamental level you can write down 2019 p10), but whether the deeper each channel particles are rather heavier than we a Lagrangian, postulate this boson- mathematics of SUSY has much to originally thought, and such models fermion symmetry and follow the do with the way this setup works [email protected] Tel: +1-510-401-5760 are still consistent with the mass of mathematics through. Then there is a I’m not sure. The case of topological www.xia.com the Higgs boson. The information you deeper picture, which is to talk about condensed-matter systems is get from unification of the couplings at additional fermionic (or quantum) potentially a more interesting place high energies also doesn’t exclude SUSY dimensions of space–time. If SUSY to explore what this particular face of particles weighing 10 TeV or so. Clearly, were to be discovered, that would be SUSY actually looks like, as you can as the masses of the sparticles increase, one of the most profound insights into study more of its properties under you have to do more fine t uning to solve the nature of reality that we could get. controlled conditions. The danger the electroweak hierarchy problem. is that, when people bandy around On t he ot her hand, t he amount of fine If SUSY is not a symmetry of nature, the idea of SUSY, often they just tuning is still many, many orders of what would be the implications for have in mind this fermion–boson magnitude less than what you’d have attempts to go beyond the SM, e.g. partnership. The real essence of to postulate without it! It’s a question quantum gravity? SUSY goes beyond that and includes

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CCJanFeb20_Interview_v2.indd 40 18/12/2019 16:10 CCJanFeb20_Interview_v2.indd 41 18/12/2019 16:13 CERNCOURIER www. V o l u m e 6 0 N u m b e r 1 J a n u ary /F e b r u a r y 2 0 2 0 CERNCOURIER.COM CERNCOURIER.COM OPINION OPINION LETTERS REVIEWS CERN Operating a future linear collider beams, and the stored energy of the drive After reading your article “Why CLIC?” beam is in the per-mill range compared to (CERN Courier November/December p41), the LHC beams. The CLIC 380 GeV acceler- Ins and outs of collider calorimetry I felt driven to comment on the issue of ator complex will have an annual energy the operability of future linear colliders. consumption corresponding to around CERN-EX-9005322 I was a member of the CLIC study team two-thirds of CERN’s accelerator com- Calorimetry for Collider question of longitudinal segmentation, under Wolfgang Schnell during the early plex today. The drive-beam production Physics, an Introduction which has a particular impact on lin- 1990s, and for a short while was responsi- and operation have been experimentally earity and calibration. ble for one option of the drive-beam pro- v e r i fie d i n t h e C L IC Te s t Fa c i l it y 3, w hic By Michele Livan and Livan and Wigmans’ book also gives a duction, the free-electron laser. I began operated until 2015. The recent devel- Richard Wigmans v a lu a bl e h i s t or i c a l o v e r v i e w o f t h e fie l d, to worry about the operability of the CLIC opment, construction and successful and corrects several erroneous interpre- Springer drive beam which, in all, would carry an operation of synchrotron light sources tations of past experimental results. The electron beam down a very narrow tube; and free-electron lasers in the past dec- authors do not shy away from criticising the equivalent power to that consumed ades have demonstrated many of the CLIC Concise and accessible, Calorimetry for calorimetric approaches in former, pres- by the Ville de Genève! The requirements concepts and beam-performance param- Linear learning whom was Raymond Stora who received Collider Physics is a reference book worthy ent and planned experiments, making on beam quality and precision steering eters. The SLC, as with many colliders, The CTF3 CLIC the Medal and the Heineman of the name. Well known experts Michele the book “juicy” reading for experts. to avoid self-destruction seemed to be had its delays and problems but ultimately test facility. Prize. Also at École Polytechnique were Livan and Richard Wigmans have written The reader will not be surprised that the beyond reasonable requirements. it produced important physics results. Jacques Prentki and Bernard d’Espagnat, an up-to-date introduction to both the authors are, for example, rather critical I then spent a year at SLAC during the Many lessons were learned and technical who later moved to CERN. Worth men- fundamental physics and the technical about highly segmented calorimeters start-up of the linear collider (SLC), where solutions developed, and these too have tioning too are Roger Nataf and Philippe parameters that determine the perfor- aiming at par t icle flow approac hes. we were thwarted by operability issues been integrated in the CLIC design. Meyer. Léon Motchane then founded the mance of calorimeters. Students and There is only limited discussion about and didn’t see a single electron–positron Institut des Hautes Études Scientifiques senior experts alike will be inspired to other aspects of calorimetry, such as collision that year. Linear colliders are Steinar Stapnes linear-collider study in 1958, the year the Lévy group made the deepen their study of the characteristics Spaghetti calorimeter Riccardo de Salvo (left) and Alois Sigrist triggering, measuring jets and inte- challenging to operate, as the SLC (the leader, CERN. fi r s t s t e p s t o e s t a bl i s h a s u m m e r s c h oolin of these instruments – instruments that at CERN in 1990 with a lead–fibre prototype that held the grating calorimeters into an overall only such facility to date) demonstrated. Cargèse. Tony Visconti and Daniel Kastler have become crucial to most contem- record for energy resolution of single hadrons for 25 years. detector concept, which may impose They must produce collisions with highly The rebirth of theory in France also launched the “Centre de Physique porary experiments in particle physics. many constraints on their mechanical focused beams that arrive simultaneously I would like to complement the excellent Théorique” in Marseilles in around 1960. Following a light and attractive intro- authors have made a remarkably strong construction. These aspects were obvi- at the collision point. (Circular machines, article “The rise of French particle phys- All of this produced wonderful results. It ductory chapter, the reader is invited impact in understanding the funda- ously considered beyond the scope of while not easy, always give the experi- ics” (CERN Courier November/December is difficult to list all the French particle to refresh his or her knowledge of the mental problems with large set-ups the book, and indeed one cannot pack menters something to do during tuning, 2019 p37), in which only the experimen- theorists who received prizes from for- interactions of particles with matter. in test beams, for example the famous everything into a single compact text- even at low luminosity.) For CLIC to provide tal side appears, with a short note about eign countries as a consequence. Key topics such as shower development, l e a d–fi br e s a m pl i n g s p a g h e t t i c a l or im- book, though the authors do include collisions that satisfy the needs of waiting developments in theory. After Louis de containment and profile, linearity and eter SPACAL. Among other issues, they a very handy appendix with tables of experimenters, both of the drive-beam Broglie’s fundamental discovery of the André Martin member emeritus of the energy resolution are discussed for both correct “myths” as to which processes parameters relevant to calorimetry. complexes must provide two exceptional, wave-particle relation λ = h/mv, which led CERN theory division. electromagnetic and hadronic compo- really cause compensation, and discuss By addressing the fundamentals of well focused, aligned and very powerful to the Schrödinger equation, theoretical nents. The authors provide illustrations quantities that correlate to the invisible calorimetry, Livan and Wigmans have electron beams that are then transported physics in France became dormant. It is Speaking up for citizen science with test-beam results and detailed energy fraction from hadrons involved provided an outstanding reference safely through the drive-beam cavities only shortly before 1950 that the signs of It was gratifying to see your brief men- Monte Carlo simulations. Practical and in the shower process, for example, to book. I recommend it highly to every- before the tuning of the main accelerating a rebirth appeared. There was the “Sémi- tion of the 42,280 citizen scientists numerical examples help the reader to measure the electromagnetic shower body interested in basic detector aspects linacs can begin. There are innumerable naire Proca” at Institut Henri Poincaré, who took part in Higgs Hunters (CERN understand even counterintuitive effects, fraction event-by-event. The topical of experimental physics. It is pleasant tweaks to be made to both beams that attended by those who needed some Courier November/December p62). As a stimulating critical thinking in detector development of the dual-readout cal- and stimulating to read, and if in addi- require feedback and feed-forward adjust- “fresh air” from outside France. In 1951 coordinator of the project, I wanted to designers, and helping the reader develop orimeter concept follows logically from tion it triggers critical thinking, so much ments. I know of no attempt to estimate Cécile DeWitt-Morette founded the Les add that the exercise yielded fascinating a feeling for the importance of the various there – a very promising future direc- the better! the time requirements to start up such a Houches Summer School of Theoretical insights into the LHC collision data – parameters t hat affect calorimet r y. tion for this central detector component, hideously complicated set of linacs, nor to Physics, where the best physicists in the such as identifying apparent “muon jets” An important part of the book is as the book discusses in considerable Peter Jenni Albert Ludwig University ensure their operation afterwards. Clearly world lectured. In Saclay a group of phys- – which were subsequently found to be devoted to hadron calorimetry. The detail. This technology would avoid the of Freiburg and CERN. the CLIC study has advanced considerably icists – Albert Messiah and his friends – the result of calorimeter punch-through during the past two decades, so I would be gave a series of lectures attended mostly, – and demonstrated the impressive capa- ATLAS: A 25-Year Insider ranging from the early days of the proto- The thrill of covered in recent review articles and the interested to learn how well the issue of at the beginning, by polytechnicians. In bility of citizen scientists to search for Story of the LHC Experiment collaboration, to the test-beam studies the chase for organisational structure is discussed on operability has been understood. 1952 Maurice Lévy, of whom I am one heavy scalars decaying within the ATLAS to verify detector concepts, the design, the Higgs the – but this volume usefully brings of the t wo first students, was invited by tracker. Particular credit is due to the 15 By The ATLAS Collaboration building and installation of the detector these various aspects together in a single Colin Johnson formerly CERN PS division. Yves Rocard to start a theoretical physics school students who performed further systems, building the event selection boson comes place w it h a unified t reat ment. World Scientific group at the École Normale Supérieure. detailed analysis and who presented the and computing environment required, through Despite the many authors who contrib- Author’s reply Lévy also taught at the university, and results to the ATLAS collaboration. We’re forming the organisation, and finally vividly uted to this book, the style and level of As you mention, the CLIC studies have in this way gathered people from out- now about to pilot a further study with ATLAS: A 25-Year Insider Story of the LHC summarising the harvest of physics gath- treatment is reasonably coherent. There developed in many respects during the side, like Jean Iliopoulos who predicted UK school students, jointly exploring the Experiment is a comprehensive overview ered thus far. Some of the chapters cover are many figures and images that augment past 25 years. For example, the power the existence of the charmed quark and student’s research questions using the of one of the most complex and successful topics that are discussed elsewhere – the the text. Those showing detector elements of the 380 GeV drive beam in its present received the Dirac Medal. CERN open-data portal. scientific endeavours ever undertaken. description of the detector summarises that are now buried out of sight are impor- design is around 18 MW, most of which At École Polytechnique, in around 1952, 117 authors collaborated to write on more extensive journal publications, the tant complements to the text descriptions: s is converted into RF power for the main Louis Michel had some students, one of Alan Barr University of Oxford. diverse aspects of the ATLAS project, major physics achievements have been the pictures of circuit boards are less

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daily 08:30 run meetings. who lived through those epochs. Finally, ration acquires? Why does every eligible Inc./ ment n i a t Enter Bros. ner r Wa DNEG/ One could imagine several audiences “Highlights of Physics Results (2010– author sign all ATLAS papers, rather than Oliver James of DNEG for this book, and I suspect that, apart 2018)” c o u l d h a v e o ffe r e d a n e x c it i n g s t ory just those who did the reported analysis? describes the science from ATLAS collaborators themselves, for non-scientists, and indeed the thrill How does the politics for choosing the col- underpinning the each reader will find different chap- of the chase for the Higgs boson comes laboration management work? Were there ters most suited to their interests. The through vividly, but with unexplained design choices that came to be regretted striking visualisations 26-page chapter “The ATLAS Detector mentions of leptons, loops and quantum in the light of subsequent experience? In in Interstellar, a nd To d a y” o ffe r s a m or e a c c e s s i bl e o v e r v i ew corrections, the treatment is at a more addition to the numerous successes, were for students just joining the collaboration technical level than would be ideal for there failures? Although I recognise that discusses trends in CQG

32 than the 300-page journal publication such readers, and the plots plucked from discussing these more intimate details the fast-growing 065001 referenced in most ATLAS publications. publications are not best suited to convey runs counter to the spirit of such large v i s u a l- e ffe c t s i n d u s t r y. Similarly, “Towards the High-Luminosity what was learned to non-physicists. collaborations, in which one seeks to LHC” gives a helpful brief introduction to damp out as much internal conflict as the planned upgrades. “Building up the Insider stor y possible, examining some of them would Oliver James is chief scientist of the Collaboration” will be useful to historians Given the words in the foreword that the have made for a more compelling book world’s biggest visual-effects studio, of science seeking to understand how sci- book is “intended to provide an insider for the non-specialist. DNEG, which produced the spec- entists, institutions and funding agencies story covering all aspects of this global The authors should be commended for tacular v isual effects for t he mov ie engage in a project whose time is ripe. science project,” I looked forward to the writing a book unlike any other I know Interstellar. DN E G’s w or k, c a r r ie d o ut Those interested in project manage- fi n a l c h a p t e r, “AT L A S C ol l a b or a t i o n: L ife of. It brings together a factual account in collaboration with theoretical ment will find “Detector Construction and its Place in Society”, to get a sense of all aspects of ATLAS’s first 25 years. cosmologist Kip Thorne of Caltech, Around the World” illuminating: this of the human dimensions of the collab- Perhaps as time passes and the partici- led to some of the most physically chapter shows how the design and fab- oration. While some of that discussion pants mellow, the companion story of the a c c u r a t e i m a g e s o f a s pi n n i n g bl a c k rication of detector subsystems is organ- is quite interesting – the collaboration’s how, in addition to the what and where, hole ever created, earning the firm A r t m e e t s s c ie n c e A variant of the black-hole disk seen in the filmInterstellar , which was created ised with several, often geographically demographics and the various outreach will also be written. an Academy Award and a BAFTA from rigorous general relativistic and other calculations. disparate, institutions joining together, activities undertaken to engage the public award for best visual effects. For each contributing according to its unique – there is a missing element that I would Paul Grannis Stony Brook University. James, it all began with an under- and The Matrix Revolutions. “There’s Suddenly these including detailed mathematical graduate degree in physics at the a big fight scene, called the Burly formalism that DNEG could then Maxwell’s Enduring Legacy: organised in 10 parts corresponding to the physics with a competent care that University of Oxford in the late 1980s. Brawl, where hundreds of digital rag-dol ls came to use in its code, and the firm was A Scientific History of the the inspiring figures who led the labo- is often difficult to find. His exciting He became interested in atomic actors get thrown around like skit- s o o n a bl e t o d e v e l o p n e w r e n d e r i n g ratory through the years, most famously accounts will stimulate an avalanche of physics, quantum mechanics and tles,” he says. “We wanted to add life and you’d find software to visualise black holes Cavendish Laboratory Maxwell himself, Thomson, Rutherford, thoughts on the development of mod- modern optics. The latter was key, realism by simulating the physics yourself wincing and . The collaboration By Malcom Longair Bragg and Mott. The numerous Nobel ern science. By returning to a time when since a great part of visual effects of these colliding bodies. The initial was so fruitful that, in 2015, James laureates who spent part of their careers Rutherford and Thomson managed the is understanding how light inter- tests looked physical, but lifeless, in sympathy and his DNEG colleagues published Cambridge University Press at the Cavendish are also nicely charac- finances of the laboratory almost from a c t s w it h s u r f a c e s a n d v olu m e s, a n d so we enhanced the simulation by t w o p a p e r s w it h T h or n e o n t h e s c i- terised, among them Chadwick, Appleton, their personal cheque book, Maxwell’s event ually enters a camera’s lens. introducing torque at every joint, as they were ence and visualisation of black holes In 1871, James Clerk Maxwell under- Kapitsa, Cockcroft and Walton, Blackett, Enduring Legacy will stimulate readers to Combining his two other pas- calculated from examples of real (Am. J. Phys 83 486 a n d Class. Quan- took the titanic enterprise of planning a Watson and Crick, Cormack and, last but r e fle c t o n t h e i nt e r pl a y b e t w e e n s c i e nce, sions – computing and photography locomotion. Suddenly these rag- bat tered about tum Grav. 32 065001). new physics laboratory for the Uni- not least, , Nobel Laureate management and technology. – l e d Ja m e s t o h i s fi r s t j o b i n a s m al dolls came to life and you’d find “The director had wanted a versity of Cambridge from scratch. To in 2019 and professor at the universities History is often instrumental in photographic studio in London, yourself wincing in sympathy as w or m h ol e w it h a n a dj u s t a bl e s h a p e avoid mistakes, he visited the Clarendon of Cambridge and Geneva. You may even understanding where we come from, but where he became familiar with the they were battered about.” The of a long and creative journey that a n d s i z e, a n d t hu s w e d e s i g n e d o n e Laboratory in Oxford and the labora- read about friends and collaborators as it cannot reliably predict directions for technical and operational aspects of sequences took dozens of artists and would culminate in the sci-fi epic w it h t h r e e f r e e p a r a m e t e r s, n a m e l y tory of William Thomson (Lord Kelvin) the exposition includes the most recent the future. Nevertheless the history of the t h e i n d u s t r y. M i s s i n g t h e i nt e l l e c- technicians months of work to create Interstellar, which tells the story of the length and radius of the worm- in Glasgow – then the best research achievements of the laboratory. Cavendish shows that lasting progress tual challenge offered by physics, just a few seconds of the movie. an astronaut searching for habitable hole’s interior as well as a third var- institutes in the country – to learn Besides the accuracy of the scientific can come from diversity of opinion, the however, in 1995 he contacted and planets in outer space. iant describing the smoothness of all he could from their experiences. descriptions and the sharpness of the inclusiveness of practices and mutual secured a role in the R&D team of Interstellar work T h e fi l m d e m a n d e d n e w i m a g ery the transition from its interior to Almost 150 years later, Malcolm Lon- ideas, this book inaugurates a useful respect between fundamental sciences. the Computer Film Company – a Following his work in ESC Enter- for black holes. Given that he hadn’t it s e x t e r i or s,” e x pl a i n s Ja m e s. “T h e gair, a renowned astrophysicist and compromise that might inspire future How can we sum up the secret of the niche studio specialising in digital tainment, James moved back to studied general relativity and had result for the was like a the Cavendish Laboratory’s head from science historians. So far as it was cus- scientific successes described in this fi l m t h at w a s p a r t o f t h e e m e r g i n g London and, after a short period only touched upon special relativ- c r y s t a l b a l l r e fle c t i n g e a c h p oi nt in 1997 to 2005, has written a monumental tomary to write biographies (or collected book? A tentative recipe might be unity London visual-effects industry. at the Moving Picture Company, it y, Ja m e s d e c i d e d t o c a l l K i p T h or n e the universe; imagine a spherical account of the scientific achievements works) of leading scientists and exten- in necessary things, freedom in doubtful A defining moment came in 2001, he finally joined Double Negative for help in finding an equation that hole in space–time.” Simulating of those who researched, worked and sive histories of various laboratories: here ones and respect for every honest scien- when one of his ex-colleagues in 2004 (renamed DNEG in 2018). describes the trajectory of light a black hole represented a bigger taught at a laboratory that has become these two complementary aspects are t ific endeavour. invited him to join Warner Bros’ He’d b e e n a t t r a c t e d b y C h r i s t o p h e r from a distant star, around a black challenge as, by definition, it is an indispensable part of the machinery happily married in a way that may lead ESC Entertainment at Alameda, Nolan’s film Begins, for hole and finally into an observer’s an object that doesn’t allow light of modern science. to further insights on the genesis of Massimo Giovannini CERN and California to work on rigid-body which the firm was creating visual eye. In total, James and Thorne to escape. With his colleagues, s The 22 chapters of the book are crucial discoveries. Longair elucidates INFN Milano-Bicocca. simulations for The Matrix Reloaded effects, and it was the beginning exchanged some 1000 emails, often he developed a completely new

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PEOPLE CAREERS PEOPLE CAREERS DNEG renderer that simulates the path N Caraban/CERN Appointments and awards of light through gravitationally CERN C Marcelloni/CERN warped space–time – including Kirkby bags aerosol award gravitational lensing effects and The 2019 Benjamin Y H

other physical phenomena that take Liu Award of the American Brice/CERN M place around a black hole. Association for Aerosol Producing an image for a motion Research, which recognises picture requires very high quality outstanding contributions to standards, and consequently ren- aerosol instrumentation and dering times were up to 100 hours experimental techniques, has compared to the typical 5–6 hours been awarded to CERN’s Jasper needed for other films. Contrary Kirkby for his investigations into to the primary goal of most astro- atmospheric new-particle and physical visualisations to achieve Inspired by physics DNEG chief scientist Oliver James, shown on the right speaking at a colloquium at CERN in cloud formation using the unique a fast throughput, DNEG needed to March 2019 organised by the Future Circular Collider study in collaboration with CERN’s EP department. The Sakurai CLOUD experiment at CERN, create images that looked like they which he originated. The award Spiro awarded Lagarrigue Prize m i g ht r e a l l y h a v e b e e n fi l m e d. “T h i s the starry background, DNEG used that software needs to be scalable rendered so they can be played back Prize recognises committee described CLOUD The 2018 André Lagarrigue Prize led us to employ a different set of the Tycho-2 star catalogue from the and adaptable to meet a wide range in real-time,” he says. “Moving to work revealing as “arguably the most effective has been awarded to Michel Spiro, visualisation techniques from those containing of skilled artists, James explains. real-time rendering means that the experiment to study atmospheric research director emeritus at of the astrophysics community – about 2.5 million stars, and more “Developing specialised simulation w or k flo w w i l l n o t r e l y o n o v e r night the potential nucleation and growth ever CEA, for the exemplary nature of techniques based on propagation of recently the team has adopted the software that gets used locally by a renders and would allow artists his career, from both a scientific L Kirkby ray bundles (light beams) instead Gaia catalogue containing 1.7 billion small group of skilled artists is one many more iterations during pro- visibility of the and managerial point of view. of discrete light rays, and on care- stars. In total, the movie notched thing but making it usable by a wide duction. We have only scratched Spiro contributed, among other

fully designed spatial filtering to up almost 800 TB of data range of artists across the globe calls the surface and there are plenty of LANL invisible axion things, to the discovery of the smooth the overlaps of neighbour- for a much bigger effort – to make it opportunities for scientists.” DNEG W and Z bosons with the UA1 UCB ing beams,” says James. Creative industry robust and much more accessible”. is currently involved in R&D to use experiment, was the initiator Another challenge was to capture With the increased use of visual Any increase in computational machine learning to enable more and spokesperson of the EROS the fact that the film camera should effects, not only for sci-fi movies resources will quickly be swallowed natural body movements or facial experiment, and played a major be traveling at a substantial frac- b ut a l s o i n d r a m a or h i s t or i c a l fi l m s, up by artists adding extra detail expressions, and is also embracing role in the GALLEX experiment. tion of the , meaning more and more scientists are work- or creating more complex simu- open-data movements. He has held several senior that relativistic aberration, Doppler ing in the field, including mathema- lations, he says, and the next big “Visual effects is a fascinating positions at CEA and CNRS and shifts and gravitational ticians and physicists. Furthermore, thing on the horizon will be real- industry where technology and from 2010–2013 was president of had to be integrated in the ren- there are a growing number of com- time simulation and rendering. hard-science are used to solve crea- the CERN Council. dering code. Things get even more panies creating tailored simulation “Today, video games are rendered tive problems,” says James. “Occa- designed and constructed, really complicated closer to the black hole packages for specific processes. in real-time by the computer’s sionally the roles get reversed and by a country mile”, and said of Polish honour for Heuer where space–time is more dis- DNEG alone has increased from 80 v i d e o c a rd, w h e r e a s v i s u a l e ffe c t s i n our creativity can have a real impact Kirkby: “His irrepressible will and On 14 October, the Henryk torted; gravitational lensing gets people in 2004 to more than 5000 movies are almost entirely created on science.” determination have adapted the Niewodniczański Institute of more extreme and the computa- people today. At the same time, as batch-processes and afterwards culture of ‘big science’ at CERN Nuclear Physics of the Polish tion takes more steps. To simulate this increase in numbers means the results are cached or pre- Panos Charitos CERN. to a major atmospheric science APS announces 2020 prizes investigations of its cosmological problem. Along the way, Jasper IFJ Appointments and awards Wesley Smith (top left) of implications. In the accelerator has also become a world-class the University of Wisconsin- arena, the 2020 Robert R Wilson aerosol scientist.” M Brice/CERN for laying the foundations of University of , first Madison, and member of the Prize was awarded to Bruce

CERN’s future projects and I am became director in 2014 and has SNOLAB CMS collaboration, has won the Carlsten (bottom left) of Los Max Planck Medal for Buras honoured to have the opportunity overseen Nikhef’s involvement American Physical Society (APS) Alamos National Laboratory for Andrzej Buras of the Technical to work with the CERN Member in international projects such 2020 W K H Panofsky Prize “for the discovery and subsequent University of Munich has been States, Associate Member States, as KM3NeT, XENON, Auger and the development of sophisticated implementation of emittance awarded the Max Planck Medal other international partners a test facility of the proposed trigger systems for particle- compensation in photo- by the German Physical Society and the worldwide particle- physics experiments, which injectors “that has enabled the for his outstanding contributions physics community.” Gianotti, enabled measuring the detailed development of high-brightness, to applied quantum field theory, who is CERN’s first female DG, partonic structure of the proton X-ray free electron lasers such as especially in flavour physics and has been a research physicist at using the ZEUS experiment at the Linac Coherent Light Source”. quantum chromodynamics. CERN since 1994 and was ATLAS R Bl i nder ma n/Ni k hef HERA and led to the discovery Among several other prizes Gianotti elected for second term spokesperson from March 2009 of the Higgs boson and the awarded in the particle, nuclear, Schnell R Academy of Sciences in Kraków On 12 December, the CERN Council to February 2013 during the Smith continues at SNOLAB completion of the Standard astrophysics and related fields, (IFJ PAN) granted former CERN unanimously decided to appoint discovery of the Higgs boson. Astroparticle physicist Nigel Model with the CMS experiment the 2020 Henry Primakoff Director-General Rolf-Dieter Fabiola Gianotti as Director- Smith has been appointed to a at the LHC”. The 2020 J J Sakurai Award for Early-Career Particle Heuer an honorary professorship General (DG) of CERN for a second Nikhef reappoints Bentvelsen three-year extension as executive Prize for theoretical particle Physics went to Matt Pyle “in recognition of his outstanding term of office of five years, with Stan Bentvelsen has been Einstein Telescope. He plans “to director of SNOLAB in Canada. physics went to Pierre Sikivie (top (bottom right above) of the contribution to the field of effect from 1 January 2021. “I reappointed for a second five- continue to open doors to new Smith, who has been in the role right) of the University of Florida University of California at experimental particle physics as am deeply grateful to the CERN year term as director of Nikhef physics through diversification of since 2009, agreed to remain in for seminal work recognising the Berkeley for his development well as his continuous support of Council for their renewed trust,” in the Netherlands. Bentvelsen, experiments, both accelerator- position until 31 December 2022, potential visibility of the invisible of high-resolution ultra-low- scientific collaboration between she said in a statement. “The an experimental physicist on based and other detectors, from with a search for a successor being axion, devising novel methods threshold cryogenic detectors for IFJ PAN and high-energy European following years will be crucial ATLAS and an academic at the physics to astroparticle physics.” revisited during 2020. to detect it, and for theoretical dark-matter searches. laboratories DESY and CERN”.

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

For advertising enquiries, contact CERN Courier recruitment/classified, IOP Publishing, Temple Circus, Temple Way, Bristol BS1 6HG, UK. Tessella is a data science, analytics and software consultancy that works with global companies 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. at the forefront of science and technology. We are leaders in the field of data science and analytics, Please contact us for information about rates, colour options, publication dates and deadlines. helping clients solve their most complex technical challenges by unlocking the power of their data, enabling them to make better-informed business decisions.

ELI Beamlines research centre in Dolní Břežany is part of The work will be predominantly focused on following topics: Our projects are varied and typically at the cutting-edge of high-tech R&D, for example: pan-European infrastructure ELI (Extreme Light Infrastructure) • development of experimental capabilities of the MAC user » Solving computational problems for chemists in drug discovery and development. » representing a unique tool of support of scientific excellence end-station with a strong focus on sample delivery and Modelling and simulating new products for FMCG clients and analysing data to improve processes. » Writing and solving complex mathematical problems to control satellites and radar systems. in Europe by making available its capacities to the best characterization techniques » Solving the computational challenges of oil and gas exploration and production, from reservoir scientific teams across the world. The aim of ELI Beamlines • participation in the support of user experiments at the modelling to writing control systems. is to establish the most intensive laser system in the world MAC user end-station as well as in-house research and and to operate it on a long-term basis. Due to ultra-high development programmes We are looking for science, mathematics and engineering graduates and postgraduates to join us. performances of 10 PW (1 petawatt = 1,000,000,000,000,000 • contribution to the relevant research activities of the RP4 Supported by our extensive training package, you will apply your deep domain knowledge and use a range watts) and concentrated intensities of up to 1024 W/cm2, we group within national and international collaborators at of skills to create and develop innovative solutions that truly make a difference in the world. can offer our users a unique source of radiation and beams synchrotrons and X-ray free-electron laser facilities of accelerated particles. The so called beamlines will enable Requirements: groundbraking research in the area of physics and science www.tessella.com | [email protected] dealing with materials, but also in biomedicine and laboratory • PhD in physics, biophysics, chemistry or related field is astrophysics and many other fields. ELI Beamlines is part of desirable. Highly motivated candidates with a M.Sc. degree the Institute of Physics of the Czech Academy of Sciences, are also encouraged to apply (in that case the position will and it was open in 2015. be transferred to a PhD student position) • strong interests in development and operation of advanced The Institute of Physics of the Czech Academy of Sciences scientific instruments is a holder of the HR Excellence in Research Award. It is • programming skills in Phyton, Matlab are beneficial awarded by the European Commission to institutions which • experience from working with lasers and/or other pulsed put significant effort into improving their HR strategy and light sources and/or vacuum equipment is beneficial ensuring professional and ethical working conditions. • strong interests in scientific fields related to biophysics, ultrafast spectroscopy and dynamics, coherent diffractive imaging, physics with ultra-short pulses, interaction of light with matter, atomic and molecular physics Ultrafast spectroscopy Researcher • good networking and communication skills, capability to work in a team As part of the experimental capabilities at ELI Beamlines, RP4 • good knowledge of spoken and written English is develops a beamline and multi-purpose user end-station for necessary as the work environment is highly international applications in AMO sciences and CDI (MAC). The MAC user We offer: end-station is equipped with electron/ion spectrometers, • the opportunity to participate in this unique scientific detectors for coherent diffractive imaging and state-of-the-art project sample delivery systems to enable advanced photon science • competitive and motivating salary experiments on low density targets (, molecules, • flexible working hours clusters, nanometer to micrometer sized organic and • nice working environment inorganic particles, vacuum compatible sub-micrometer size • career growth liquid sheets and aerosols). • lunch vouchers, pension contribution and 5 sick days • support of leisure time activities We are now looking for a researcher/instrumental scientist to contribute to the development of the unique experimental capabilities of the MAC user end-station. The successful Applications, containing CV, cover letter, contacts of candidate will participate in all aspects of the MAC station references, and any other material the candidate considers operations but assume a specific responsibility for the relevant, should be sent to Mrs. Jana Ženíšková, HR implementation and further development of various sample specialist ([email protected], +420 - 601560322). delivery systems (molecular and cluster beams, gas dynamic Information regarding the personal data processing and virtual nozzle and electrospray nano-particle injection, access to the personal data at the Institute of Physics of production of flat liquid sheets). This work also includes the the Czech Academy of Sciences can be found on: development of characterization methods for samples and https://www.fzu.cz/en/processing-of-personal-data sample delivery techniques. Following completion of the ELI Beamlines facility she/he will work both on independent research topics focused on ultrafast spectroscopy and CERN’s HR Talent Acquisition team wishes you a very happy new year! imaging of nano-particles and molecular beams as well as provide support for members of an international user 2020 will see plenty of new opportunities opening up for students, graduates and experienced professionals. community who come to perform experiments at the Find out more and apply now: https://careers.cern. scientific end stations. You too could experience working in a place like nowhere else on Earth. CERN. Take part!

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Luigi R adicati 1919–2019 Eminence in symmetry

Luigi Radicati, one of the emi- Superiore Normale Scuola nent Italian theoretical physicists ACCELERATORACCELERATOR of the past century, passed away on 23 August 2019 in his home in Pisa, about 50 days before his 100th birthday. Born in Milan, Radicati received his laurea in physics from the ASTRO THEORY University of Torino under the supervision of Enrico Persico in 1943, and became the assistant professor of Eligio Perucca at Torino Polytechnic in 1948. In between this, during the Second World War he was also a member of a p a r t i s a n d i v i s i o n fi g ht i n g a g a i n s t German occupation. The years 1951-1953, which Radicati spent as a research fellow PHOTON PARTICLE at the University of Birmingham in the group of Rudolf Peierls, had a major impact on his training. Then, in 1953 Radicati became a professor of theoretical physics, first at the University of Naples and two years later at the University of Pisa. In ENGINEERING 1962 Radicati was finally called to Theorist Luigi Radicati turned his attention to nuclear and particle physics, astrophysics, plasma physics and the Scuola Normale Superiore (SNS) statistical physics. in Pisa as one of two professors in the “Classe di scienze”, the other 1962 and at the beginning of 1964 Radicati’s SNS Gilberto Bernardini, who acted being the great mathematician had proposed, simultaneously with as SNS director from 1964 to 1977, Ennio De Giorgi. Radicati remained George Zweig, the notion of quarks. collaborations and Emilio Picasso, who was SNS at SNS until 1996, acting as vice- The SU(6)-subgroup SU(3) × SU(2) director from 1992 to 1996. director between 1962 and 1964, puts together Gell-Mann’s SU(3) brought frequent Radicati was a member of the and director between 1987 and 1991. with the spin SU(2) symmetry, Accademia Nazionale dei Lincei Luigi Radicati can be remem- thus unifying in single multiplets visits of eminent from 1966, named Chevalier de la bered for two main reasons: the the pseudo-scalar together with physicists to Pisa Légion d’Honneur and Doctor Hon- special role that he attributed to the vector mesons and the J = 1/2 oris Causa at the École Normale in symmetries; and the broadness of together with the J = 3/2 bary- in 1994, and was awarded the his interests in physics, as in the ons. At a deeper level, SU(6) gave honour of Cavaliere di Gran Croce of relations between physics and other momentum to view the quarks as detector consisting of a system of the Italian Republic in 2004. During disciplines. His most important and real entities obeying peculiar sta- two radio-frequency cavities, cou- his career, he also translated and well known physics results stem tistics, preliminary to the intro- pled to create a two-level system introduced important physics books from the early 1960s. After working duction of colour. w it h a t unable difference bet ween into Italy, including The Meaning with Paolo Franzini to show evi- In the latter part of the 1960s Rad- their oscillation frequencies. of Relativity by , dence for SU(4) symmetry in the icati began turning his attention to Radicati’s collaborations brought A History of Science by William classification of nuclear states, astrophysics, gravity, plasma phys- frequent visits of eminent phys- Dampier and Quantum Mechanics introduced by Wigner in 1937, in ics and statistical physics. Here it is icists to Pisa, among them Free- by Leonard Sc hiff. 1964 Radicati proposed, together worth mentioning the long-lasting man Dyson, Feza Gürsey, T D Lee, Luigi Radicati is survived by his with Feza Gürsey, the enlargement collaboration with Emilio Picasso, Louis Michel, Rudolf Peierls, David wife and four of his sons. of SU(4) to SU(6) as a useful sym- which started in 1977 during a Speiser and John Wheeler. Most of metry of hadrons. Gell-Mann had discussion in the CERN cafeteria: all, Radicati played a prominent Riccardo Barbieri Scuola Normale www.desy.de/career introduced the SU(3) symmetry in the use of a gravitational-wave role in bringing from CERN to the Superiore, Pisa.

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Jean-Pierre BlaSer 1923–2019 1960s, extended his previous meas- which was started by Sreekantan and field stations. In 1992, after a and philosophical basis. He remained urements of muon intensity to the and his collaborators in Ooty in the long and eventful scientific carrier an alert and active researcher and d e e p e s t l e v e l a v a i l a bl e; fi n a l l y, a f t e r 1970s, is being continued in Ladakh at TIFR, Sreekantan moved to Ben- was engaged in his academic activ- Pushing cyclotron limits reaching a depth of 2700 m, record- with a low-energy threshold. galuru and was offered a chair at the ities with great eagerness until the ing no muons after two months of Sreekantan became director of newly created National Institute of very end. His death marks the end of Jean-Pierre Blaser, a former direc- Blaser pioneered The first step, for which a supercon- exposure. Sreekantan and his col- TIFR in 1975, and over the next 12 Advance Studies. His research inter- a glorious chapter of experimental

tor of the Swiss Insitute of Nuclear N Blaser ducting solenoid was constructed, laborators realised that such a deep years steered the institute with est shifted from physical sciences to cosmic-ray research in India. Research (SIN), passed away in his the use of pions was to use pions for the treatment underground site with minimal cos- distinction and left a rich legacy of the philosophical aspects of science home in Switzerland on 29 August of deep-seated tumours. In 1984 mic-ray muon background would high-quality research programmes and in particular to the abstract topic Naba K Mondal Saha Institute of 2019 at the age of 96. for the treatment the irradiation of eye tumours be an ideal site to detect atmos- as well as several new TIFR centres of consciousness and its scientific Nuclear Physics, Kolkata. I n 1948 Bl a s e r fi n i s h e d h i s p hys- started, using protons, and to date pheric neutrinos. A series of seven ics studies at ETH Zurich, going on of deep-seated more than 7000 patients have been neutrino telescopes were quickly to participate in the development tumours treated. Later, a new superconduct- set up at a depth of 2300 m and in of a cyclotron at ETH built by Paul ing cyclotron was acquired and two early 1965 they recorded the first Scherrer during the Second World more gantries are now in operation. atmospheric-neutrino event, con- War. From 1952–1955 he carried cialists like the late Henry Blosser Blaser strongly supported all activ- temporaneously with the detection out experiments with mesons at had doubts that the SIN crew would ities in the medical application of from another underground neutrino the synchrocyclotron in Pitts- reach the ambitious design goal of a cyclotrons, and gave his advice to experiment set up by Fred Reines burgh before becoming director of 100 µA beam current. But Blaser and a new cyclotron project in South in a South African mine. It was an the observatory in Neuchâtel from Willax were convinced, anticipat- Africa – becoming elected as a for- important milestone, given how 1955–1959. In 1959 he was appointed ing that the original 72 MeV injec- eign associate of the Royal Society important the study of neutrinos as Scherrer’s successor and inher- tor cyclotron would be the limiting of Sout h A frica for his effor ts. underground would later become. ited from him the planning group Accelerator physicist Jean-Pierre factor and eventually would have Jean-Pierre Blaser was blessed During early 1980s Sreekantan for a new cyclotron. Originally, Blaser was instrumental in getting the to be replaced. In January 1974 the with great intuition based on a thor- and his collaborators built two Scherrer wanted to copy the 88-inch Swiss national cyclotron approved. first protons were extracted from ough knowledge of the basic laws detectors, one at a depth of 2300 m cyclotron at Berkeley and use it for the ring, and at the end of 1976 of physics. He was open to new and and the other at 2000 m, to study the research in nuclear physics, but rate sectors to leave space for high- the design current of 100 µA was unconventional ideas and he fully stability of the proton. These two Blaser wanted something more voltage cavities. Blaser immediately reached. More highlights followed, motivated young scientists with his experiments ran for more than a ambitious. After receiving advice supported the idea and pushed to right up to 2009 with 2.4 mA pro- trust in their abilities. In his free decade and put strong limits on the from accelerator experts at CERN, get this expensive project approved tons at 590 MeV and a new world time he enjoyed exploring the land- among them Pierre Lapostolle, he by the Swiss government. Against record of 1.4 MW in average beam scapes of Switzerland either by foot Sreekantan quickly proposed a 500 MeV cyclotron for all odds and against some strong power achieved – a record that still or as a pilot with a light aeroplane. the production of mesons. o p p o s it i o n, h e fi n a l l y s u c c e e d e d. I n holds today. These results gave Bla- But his top priority was his family. recognised the The key for such a meson factory 1968 he founded SIN in Villigen and ser great satisfaction, even after his He enjoyed enormously the com- was to extract the high-intensity was its director for the next 20 years. retirement in 1990. Before that date pany of his wife Frauke, their two importance of the proton beam with very low losses. In a last-minute decision, based he initiated in 1988 the new Paul daughters Claudine and Nicole, and The leader of Blaser’s cyclotron on results of CERN experiments Scherrer Institute (PSI), a combi- their four grandchildren. In Jean- emerging field of X-ray group, Hans Willax, realised that a which showed that the production nation of SIN and the neighbouring Pierre, his family and the accelerator astronomy conventional cyclotron would have of pions would strongly increase reactor institute EIR. community loses a great personality. high losses at extraction and in 1962 with energy, the energy of the SIN From the start of the accelerator had the brilliant idea to break up cyclotron was increased from 500 to project, Blaser saw the potential of Werner Joho Paul Scherrer Institut, proton lifetime. He was also instru- the cyclotron magnets into sepa- 590 MeV. Even top accelerator spe- particle beams to irradiate tumours. Switzerland. mental in starting a high-altitude cosmic-ray laboratory at Udhag- B V Sreek antan 1925–2019 amandalam (Ooty) in the State of Tamil Nadu to study the hadronic components of cosmic-ray showers. Remembering a cosmic-ray pioneer Sreekantan quickly recognised the importance of the emerging R Sreekantan Badanaval Venkatasubba Sreekan- formed Tata Institute of Fundamen- field of X-ray astronomy for prob- tan, a pioneering cosmic-ray physi- tal Research (TIFR) in Mumbai. ing high-energy processes in the cist and a member of Homi Bhabha’s Attracted by Bhabha’s charisma, he universe. In 1967 he started bal- team of scientists, who played an joined TIFR in July 1948 and began loon-borne experiments to study important role in the development a long, illustrious scientific career cosmic X-ray sources and built a of post-colonial Indian science, of almost 44 years. strong group that went on to develop died at his home in Bangalore on In 1951 Bhabha sent Sreekantan expertise in the fabrication of highly 27 October 2019. down the deep Champion Gold sophisticated X-ray detectors for Sreekantan was born on 30 June Mine at Kolar Gold Fields (KGF) near space-borne astronomy missions. 1925 near Mysore in South India. Bengaluru to measure the flux of The multi-wavelength astronomy After receiving his master’s degree cosmic-ray muons at varying observatory Astrosat, launched by in physics in 1947 with a speciali- depths. This pioneering initiative the Indian Space Research Organ- sation in wireless technology from not only earned Sreekantan a PhD isation in September 2015, is a tes- Mysore University, he joined the but also paved the way for setting timony to the strength of the group. Indian Institute of Science at Ben- up a deep underground laboratory. A very high-energy gamma-ray galuru as a research scholar, where Badanaval Venkatasubba Sreekantan led several key experiments in A series of follow-up experiments observation programme using the he heard about Bhabha and his newly the Kolar Gold Fields mine. at KGF, carried out during the early atmospheric Cherenkov technique,

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CCJanFeb20_Obits_v3.indd 52 18/12/2019 16:19 CCJanFeb20_Obits_v3.indd 53 18/12/2019 16:19 CERNCOURIER www. V o l u m e 6 0 N u m b e r 1 J a n u ary /F e b r u a r y 2 0 2 0 CERNCOURIER.COM BAROU HIGH VOLTAGE. EXACTLY. POWER FOR MODERN DETECTORS MODULAR LOW AND HIGH VOLTAGE MULTICHANNEL POWER SUPPLY SYSTEMS N MMS MMS HV LV Outreach feels the force rom the archie anuaryebruary compatible compatible STELLAr or Capitalising on the release of he STELLAthe Satellite Transmission Experiment ise o Skywalker last month, UK- Linking Laboratoriesis taking shape, with a 3-m based physicists at the Cockroft diameter antenna installed at CERN, right. This Institute and the University of CERN 196.11.79 pioneering project will allow European physics University Liverpool of Liverpool on 20 November used laboratories to explore the possibility of high-speed Star ars to engage local school data transmission – 1 Mbits – over large distances children with accelerator physics. using the European Space Agency’s OTS-2 We need more scientists and communications satellite, launched in 1978. engineers, said Liverpool’s STELLA will link CERN, the UK Rutherford Laboratory, DES in Carsten Welsch. There has been a fall in interest in these disciplines, Germany, Saclay in France, Pisa in Italy, Dublin in Ireland and Graz in and for us today, Star ars is the icebreaker. Welsch linked the proton Austria. It is supported by the European Space Agency (ESA), the torpedo used by Luke Skywalker to destroy the death star to hadron European Economic Community (EEC) and the national post and therapy, and the hovering speeder bikes seen on the forest moon of telegraph (PTT) authorities. Endor to superconductivity and future colliders. Lightsabres CERN experiments will provide the bulk of transmitted data until provoked discussions on the laser knives used for precision surgery the big shutdown, when the SPS stops and work begins on its and materials treatment, and students sliced virtual cubes using conversion into a proton–antiproton collider. For the remainder of the virtual-reality headsets and controllers. Experiments with year DES will be the main user, with data for Rutherford and Saclay. liquid nitrogen heightened awareness of Han Solo’s precarious  Compiled from text on pp444–5 of ourier JanFeb 1980. situation when frozen in carbonite – and also of the LHC’s ultra-low-temperature vacuum pipes. Finally, force telekinesis led to conversations about the Paul traps used to capture antihydrogen ompilers note SA was a test bed or technologies that would be ions in experiments such as GBAR at CERN. crucial to the omputing Grid and the eb. SA edia corner “There they are, theoretical Phase , , demonstrated the technical physicists in their natural easibility o accurate high-speed, high-volume data highest channel density to save valueable installation space “To set up mathematical equations habitat, sitting at desks deep transmission between uropean laboratories. In where you have a particle that in contemplation or scrawling SA Phase , , the Pisa collaborators best ripple and characteristics interacts with and indecipherable formulae on implemented an interconnection protocol unctionally electrons more than with protons whiteboards, trying to fi gure euivalent to the Internet Protocol while uropean governments engaged and neutrinos turns out to be not so out where all the dark matter in internecine communication protocols battles, lagging behind the S in up to 30 kV, up to 100 W per channel simple to do.” is hiding.” adopting PIP. ntil , s migration to the internet was heavily criticised; by 1991 the Lab was the hub for 80% of Europe’s internet traffi c. pure LV compatible, pure HV compatible and mixed setup crates available Theorist Matt Strassler in Scientifi c The Observer (1 December) American (9 December) on the reporting on a visit to CERN. prospects for the existence of the high class & quality precision low and high voltage supplies 17 boson (see p7). “The project – known as the uration of the shortest eer U interchangeable controller boards for networking and software control Electron-Ion Collider of China, laser pulse enabling ultrafast “The remarkable progress of or EICC – will see electrons underground dark-matter being fi red at the nuclei of heavy spectroscopy of biochemical detectors and the LHC has thrown elements such as iron or uranium fs processes and one of seeral FLEXIBLE cosmology into a state of major at high speeds.” superlaties released by ES to CHANNEL disruption.” South China Morning Post (16 mar its th anniersary COMBINATIONS Fermilab’s Dan Hooper writing December) reports plans to create a BY MODULAR CHANNELS

on dark matter’s increasing paradise for physicists in China. Studio Sandbox elusiveness in ime (6 December). Signing for science “A hall to house the tank will ATLAS postdoc Giordon Stark of the “CERN’s boss Fabiola Gianotti be dug with explosive charges University of California, Santa Cruz, in is right to be proud of the spirit at a site 8 km from the existing conjunction with sign-language experts, of common human purpose her Kamioka facilities, to avoid has developed a sign for particle collision OPC-UA, SNMP organisation embodies… Is it dewy- vibrations disturbing the KAGRA – one of several being contributed to the eyed idealism to suggest that this is gravitational-wave detector, lexicon of American Sign Language to a model we might apply elsewhere?” which is about to start operating.” help deaf scientists communicate. Stark, who himself is deaf, argued NEW EHS FLEX HV Boards High Class Low Voltage Boards Controller Boards with Linux inside From a New Scientist editorial Nature (16 December) reporting on that the sign couldn’t just show two fi sts crashing together and then (23 November) arguing for a High Voltage Supply highly up to 16 channel LV for on site integrated EPICS IOC, SNMP, the green light for construction coming to a stop, since that isn’t technically accurate, and settled on OPC-UA and Webservices, research institution dedicated to customizable through plug- frontend hardware supply saves of the Hyper-Kamiokande the signer sending their hands past one another and then fl icking gable channels (by factory) cable and installation space also „bare metal“ use climate change. experiment in Japan. t heir fi ngers out to show t he result ing sprays of par t icles.

54 CERN COURIER JANUARY/FEBRUARY 2020 WWW.WIENER-D.COM | WWW.ISEG-HV.COM/MMS

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