CERNSeptember/October 2019 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the September/October 2019 issue of CERN Courier. During the final decade of the 20th century, the Large Electron Positron collider (LEP) took a scalpel to the subatomic world. Its four experiments – ALEPH, DELPHI, L3 and OPAL – turned high-energy particle physics into a precision science, firmly establishing the existence of electroweak radiative corrections and constraining key Standard Model parameters. One of LEP’s most important legacies is more mundane: the 26.7 km-circumference tunnel that it bequeathed to the LHC. Today at CERN, 30 years after LEP’s first results, heavy machinery is once again carving out rock in the name of fundamental research. This month’s cover image captures major civil-engineering works that have been taking place at points 1 and 5 (ATLAS and CMS) of the LHC for the past year to create the additional tunnels, shafts and service halls required for the high-luminosity LHC. Particle physics doesn’t need new tunnels very often, and proposals for a 100 km circular collider to follow the LHC have attracted the interest of civil engineers around the world. The geological, environmental and civil-engineering studies undertaken during the past five years as part of CERN’s Future Circular Collider study, in addition to similar studies for a possible Compact Linear Collider up to 50 km long, demonstrate the state of the art in tunnel design and construction methods. Also in this issue: a record field for an advanced niobium-tin accelerator dipole magnet; tensions in the Hubble constant; reports on EPS-HEP and other conferences; the ProtonMail success story; strengthening theoretical physics in DIGGING southeastern Europe; and much more. FOR To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier PHYSICS To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier Exploring LEP’s legacy Hubble constant questioned Accelerator magnet breaks record EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING CCSeptOct19_Cover_v6.indd 1 29/08/2019 08:46 CERNCOURIER www. V OLUME 5 9 N UMBER 5 S EPTEMBER / O CTOBER 2 0 1 9 CERNCOURIER.COM IN THIS ISSUE V OLUME 5 9 N UMBER 5 S EPTEMBER /O CTOBER 2 01 9 It’s Time for a New Generation Fermilab of Power Solutions! NASA and ESA CERN-AC-9107004_2-1 FOR RESISTIVE AND SUPERCONDUCTING MAGNETS CT-BOX Dipole development US researchers have set a record for Life at LEP Accelerator physicists Hubble discrepancy Nobel-laureate Adam All-In-One Current Measurement and Calibration System accelerator-magnet field strength. 7 combined acumen with grit at a collider Riess discusses the accelerating expansion of Up to ±1.000 A, 1 ppm/K TC, 100 ksps Data-Logger and Oscilloscope that transformed the field. 39 the universe. 47 CT-Viewer software included with Ethernet, Serial and USB NEWS PEOPLE EASY-DRIVER ±5 A and ±10 A / ±20 V Bipolar Power Supply Series ANALYSIS ENERGY FRONTIERS FIELD NOTES CAREERS Record dipole field CMS revisits rare and EPS-HEP looks ahead From SUSY to the Full-Bipolar operation, Digital Control Loop, Ethernet Connectivity ProtonMail Device supported by Visual Easy-Driver software • Astroparticle-theory beautiful decays • Higgs hunting boardroom centre • Breakthrough • Bottomonium • Between desert and ProtonMail’s founders Prize for Supergravity elliptic-flow no-show swampland • Humboldt left academia with the FAST-PS-M • CERN and ESA join • ATLAS pursues Higgs Kolleg • Cold-atom goal of making e-mail Digital Monopolar Power Supplies - up to 100 A forces • MedAustron properties • LHCb interferometry • FCC account holders the High-Precision Monopolar Power Converters with Gigabit Ethernet • Galaxy simulation • chases charged-lepton week • Strangeness in client rather than the Embedded Linux OS, device supported by Visual PS software Cloud computing. 7 flavour violation.15 Quark Matter • Muon product. 53 g−2. 19 FAST-PS FEATURES Digital Bipolar Power Supplies - up to ±30 A and ±80 V Full-Bipolar, Digital Control Loop, High-Bandwidth, 10/100/1000 Ethernet TUNNEL ENGINEERING LEP’S PHYSICS LEGACY THE STORY OF LEP Embedded Linux OS, device supported by Visual PS software Tunneling for LEP’s electroweak The greatest lepton physics leap collider The civil engineering 519-529 (1989) B231 30 years ago, ALEPH, Steve Myers tells LEP’s FAST-PS-1K5 underpinning proposals story from conception Digital Bipolar Power Supplies - up to ±100 A and ±100 V Phys.Lett. DELPHI, L3 and OPAL for a future collider. 26 embarked upon a physics to its emotional final 1.500 W, Paralleling via SFP/SFP+, 1 ppm/K TC, 10/100/1000 Ethernet M Br ice/CER N-PHO T O-201908-213-1 tour de force. 32 day. 39 Embedded Linux OS, device supported by Visual PS software NGPS OPINION DEPARTMENTSCERNSeptember/October 2019 cerncourier.com COURIERReporting on international high-energy physics High-Stability 10-kW Power Supply - 200 A / 50 V Digital Control Loop, Paralleling via SFP/SFP+, 10/100/1000 Ethernet VIEWPOINT INTERVIEW REVIEWS FROM THE EDITOR 5 Embedded Linux OS, device supported by Visual PS software Building Balkan Grappling with The cutting edge of NEWS DIGEST 13 bridges in theory dark energy cancer research APPOINTMENTS 56 European support is vital Adam Riess discusses The Physics of Cancer & AWARDS to build capacity in discrepancies in the CERN and the Higgs • RECRUITMENT 58 southeastern Europe. 45 Hubble constant. 47 Boson Subatomic On the cover: DIGGING • DEEP FOR Desire. 51 A road-header at point PHYSICS 5 in BACKGROUND 62 August,Exploring LEP’s legacy preparing for the Questioning Hubble’s constant high-luminosityAccelerator magnet breaks record LHC upgrade. (M Brice/CERN.) 26 www.caenels.com CERN COURIER SEPTEMBER/OCTOBER 2019 3 CernCourier_CAENels_December_BFC.indd 1 25/10/18 18:11 CCSepOct19_Conts_v5.indd 3 29/08/2019 08:49 CERNCOURIER www. V OLUME 5 9 N UMBER 5 S EPTEMBER / O CTOBER 2 0 1 9 CERNCOURIER.COM FROM THE EDITOR Boring matters CERN-AC-8701958 u r i ng t he fi n a l de c ade of t he 20t h ce nt u r y, t he L a rge E le c t ron Posit ron col l ider (LEP) to ok a sc a lp el to t he Ds u b a t o m ic w orl d. It s fo u r e x p e r i m e nt s – A L E PH, DE L- PHI, L3 and OPAL – turned high-energy particle physics i nt o a pr e c i s io n s c ie n c e, fi r m l y e s t a bl i s h i n g t h e e x i s t e n c eof e l e c t r o w e a k r a d i a t i v e c or r e c t io n s. L E P’s pr o g r a m m e d e t e r- m i n e d t h e nu m b e r o f n e ut r i n o f a m i l ie s t o b e t h r e e, o b s e r v e d Matthew the running of the QCD coupling constant and severely con- Chalmers strained key Standard Model parameters, to name a few Editor highlights (see p32). The machine broke new ground in the s c a l e o f pr oj e c t s i n h i g h- e n e r g y p h y s i c s, a n d e nj o y s a pr o u d place in the memories of those who worked on it (p39). One of LEP’s most important legacies, however, is the 26.7 km- c i r c u m fe r e n c e t u n n e l t h a t it b e q u e a t h e d t o t h e L HC. W it h o ut it, the rich seam of physics that is the exploration of the Higgs sector might st ill be buried. Today at CERN, 30 years after LEP’s first results, heavy m a c h i n e r y i s o n c e a g a i n c a r v i n g o ut r o c k i n t h e n a m e o f f u n- Heroic The LEP tunneling crew in January 1987 having completed damental research. Since June 2018, major civil engineering the arc from point 2 to point 3 with only 1 cm of difference. works have been taking place at points 1 and 5 (ATLAS and CMS) of the LHC to make way for the high-luminosity LHC. pinned a highly successful research programme spanning Each site requires a new shaft of 80 m deep, a service hall to a l most 50 yea rs (a nd p erhaps e ven longer), t he FCC’s lepton- house cryogenic and other equipment, a 300 m-long tunnel and subsequent hadron-collider modes would serve particle for electrical equipment and four 50 m service tunnels that physicists to at least the end of the 21st centur y. Sensing the will connect the new structures to the accelerator tunnel. By opportunity, China is drawing up plans for a similar pro- t h e t i m e t h e u n d e r g r o u n d s t r u c t u r e s a r e c o m pl e t e d i n 202 1, a gramme, benefitting from lower construction costs compared tot a l of a rou nd 100,000 m 3 of ea r t h w i l l h ave b e e n e xc av ate d.