CERN Courier–Digital Edition

CERNCOURIER <ul style="display: flex;"><li style="flex:1">March/April 2021 cerncourier.com </li><li style="flex:1">Reporting on international high-energy physics </li></ul>W E L C O M E CERN Courier – digital edition Welcome to the digital edition of the March/April 2021 issue of CERN Courie r. Hadron colliders have contributed to a golden era of discovery in high-energy physics, hosting experiments that have enabled physicists to unearth the cornerstones of the Standard Model. This success story began 50 years ago with CERN’s Intersecting Storage Rings (featured on the cover of this issue) and culminated in the Large Hadron Collider (p38) – which has spawned thousands of papers in its first 10 years of operations alone (p47). It also bodes well for a potential future circular collider at CERN operating at a centre-of-mass energy of at least 100TeV, a feasibility study for which is now in full swing. Even hadron colliders have their limits, however. To explore possible new physics at the highest energy scales, physicists are mounting a series of experiments to search for very weakly interacting “slim” particles that arise from extensions in the Standard Model (p25). Also celebrating a golden anniversary this year is the Institute for Nuclear Research in Moscow (p33), while, elsewhere in this issue: quantum sensors target gravitational waves (p10); X-rays go behind the scenes of supernova 1987A (p12); a high-performance computing collaboration forms to handle the big-physics data onslaught (p22); Steven Weinberg talks about his latest work (p51); and much more. <ul style="display: flex;"><li style="flex:1">HA </li><li style="flex:1">DR </li><li style="flex:1">ON </li><li style="flex:1">CO </li><li style="flex:1">LL </li></ul><ul style="display: flex;"><li style="flex:1">IDE </li><li style="flex:1">RS </li></ul><ul style="display: flex;"><li style="flex:1">50 y </li><li style="flex:1">ear </li><li style="flex:1">s of </li><li style="flex:1">dis </li><li style="flex:1">cov </li></ul>ery <a href="/goto?url=http://comms.iop.org/k/iop/cerncourier" target="_blank">To sign up to the new-issue alert, please visit: </a><a href="/goto?url=http://comms.iop.org/k/iop/cerncourier" target="_blank">http://comms.iop.org/k/iop/cerncourier </a><a href="/goto?url=https://cerncourier.com/p/about-cern-courier" target="_blank">To subscribe to the magazine, please visit: </a><a href="/goto?url=https://cerncourier.com/p/about-cern-courier" target="_blank">https://cerncourier.com/p/about-cern-courier </a>EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING ATLAS spots rare Higgs decay  Weinberg on effective field theory  Hunting for WISPs <a href="/goto?url=http://cerncourier.com" target="_blank">WWW</a><a href="/goto?url=http://cerncourier.com" target="_blank">.</a><a href="/goto?url=http://cerncourier.com" target="_blank"> </a><a href="/goto?url=http://cerncourier.com" target="_blank">CERN</a><a href="/goto?url=http://cerncourier.com" target="_blank">COURIER </a>V o l u m e 6 1 N u m b e r 2 m a r c h / a p r i l 2 0 2 1 CERNCOURIER.COM Your DIGITAL POWER ELECTRONICS Partner Volume 61 Number 2 march/april 2021 IN THIS ISSUE It’s ALL about the DETAILS Dalitzdecay ATLA S s pot s r ar e d eca y o f t h e H igg s b oson UniversalsearchBaikal-GVD will continue the StaffsearchCERN’s efforts to attract <ul style="display: flex;"><li style="flex:1">to a photon and a low-mass electron or muon pair. 17 </li><li style="flex:1">astrophysical neutrino search. 33 </li><li style="flex:1">non-physicists into ke y r oles. 61 </li></ul><ul style="display: flex;"><li style="flex:1">NeWS </li><li style="flex:1">people </li></ul><ul style="display: flex;"><li style="flex:1">ANALYSIS </li><li style="flex:1">ENERGY FRONTIERS </li><li style="flex:1">FIELD NOTES </li><li style="flex:1">CAREERS </li><li style="flex:1">OBITUARIES </li></ul>AEgIS on track to test antimatter free fall First evidence for rare Higgs-boson decay Tooling up to hunt dark Jack Steinberger Martinus Veltman Günther Plass Acceleratingtalent at CERN The challenge of attracting engineers, technicians and others who build and maintain CERN’s complex infrastructure. 61 •••••••matter Computing •NICA sees first beam CLOUD and Arctic sea Supersymmetry collaboration kicks off <ul style="display: flex;"><li style="flex:1">•</li><li style="flex:1">•</li></ul>searches Precision Quark-matter fireballs in Protvino. 21 André Martin <ul style="display: flex;"><li style="flex:1">•</li><li style="flex:1">•</li><li style="flex:1">•</li></ul><ul style="display: flex;"><li style="flex:1">ice Quantum sensing </li><li style="flex:1">leap for B0s Light shines </li></ul>Stephanie Zimmermann Stephen Reucroft Jean-Claude Berset. 69 <ul style="display: flex;"><li style="flex:1">•</li><li style="flex:1">•</li></ul><ul style="display: flex;"><li style="flex:1">Farewell Daya Bay </li><li style="flex:1">inside lead nuclei. 17 </li></ul>•The core of SN1987A. 7 •FeaTureS <ul style="display: flex;"><li style="flex:1">WISPS </li><li style="flex:1">INR RAS </li><li style="flex:1">HADRON COLLIDERS </li><li style="flex:1">LHC </li></ul>Insearchof WISPs New experiments will expand the search for axions and other weakly interacting ‘slim’ particles that could hail from far above the TeV scale. 25 Discoverymachines Lyn Evans and Peter Jenni look at the lessons learned from 50 years of experience with hadron colliders and their detectors. 38 A decadeinLHC publications Alex Kohls, Jens Vigen and Micha Moskovic look back on the Russia’sparticle- physicspowerhouse The Institute for Nuclear Research in Moscow continues to leave its mark on neutrino and high-energy physics. 33 first 10 years of LHC publications. 47 DeparTmeNTS opiNioN <ul style="display: flex;"><li style="flex:1">VIEWPOINT </li><li style="flex:1">INTERVIEW </li><li style="flex:1">REVIEWS </li></ul>FROM THE EDITOR 5 15 Power Supply Systems Connectingphysics withsociety We must communicate the applications and impact of our field, argues Barbora Bruant Gulejova. 49 Stillseeking solutions Steven Weinberg reflects on effective field theory and his latest attempt to understand the fermion mass hierarchy. 51 Thehitchhiker’s guidetoweakdecays An expedition to NEWS DIGEST Precision Current Measurements Beamline Electronic Instrumentation FMC and MicroTCA APPOINTMENTS &AWARDS 62 new physics summits RECRUITMENT BACKGROUND 64 74 Onthecover: CERN’s Intersectin g S torag e R ings, the firs t h adron collider. 38 The science of learning physics. 57 •<a href="/goto?url=http://www.caenels.com" target="_blank">www.caen</a><a href="/goto?url=http://www.caenels.com" target="_blank">els.com </a>CERN COURIER MARCH/APRIL 2021 3<a href="/goto?url=http://cerncourier.com" target="_blank">WWW</a><a href="/goto?url=http://cerncourier.com" target="_blank">. </a><a href="/goto?url=http://cerncourier.com" target="_blank">CERN</a><a href="/goto?url=http://cerncourier.com" target="_blank">COURIER </a>V o l u m e 6 1 N u m b e r 2 m a r c h / a p r i l 2 0 2 1 CERNCOURIER.COM edwardsvacuum.com FROM THE EDITOR ENABLING RESEARCH IN UHV Edwards are able to supply a total vacuum package from UHV through to atmospheric pumping from a range of products including: • Primary pumps nXDS dry scroll pumps and RV oil sealed rotary vane pumps for excellent ulꢀmate and superior vapour handling With our advanced modelling Therewardsof boldthinking • Ultra-high vacuum Gamma Ion pumps for low cost and vibraꢀon free operaꢀon capabiliꢀes and years of experience in scienꢀfic research, rest assured Edwards has the vacuum experꢀse to meet your applicaꢀon requirements. ack in the early 1960s, as this month’s cover feature Europeanstrategyforparticlephysics, CERNisexploringthe describes (p38), discussion raged at CERN about the mostambitiouslong-termtechnologicalpathinundertaking nextbeststepforparticlephysics.Atthetime,thehigh- a feasibility study for a future circular hadron collider with a energyfrontierwascommandedbythegreatprotonsynchro- centre-of-massenergyofatleast100TeV. Ifbuilt, thesuccess trons, such as Brookhaven’s Cosmotron and, later, CERN’s ofthismotherofallhadroncolliderswillhaveeachgeneration Proton Synchrotron, which drove fixed-target experiments. of previous machine and its detectors to thank. Butanewtypeofmachinecapableofexploitingthefullenergy • High vacuum nEXT and STP turbomolecular pumps including versions for high throughput and radiaꢀon hardened designs B<a href="mailto:[email protected]" target="_blank">[email protected] </a>Matthew Chalmers Editor of proton beams for the production of new particles – the Know your limits hadron collider – was revving up in the sidelines. In Decem- As productive as hadron colliders are in probing nature at ber 1965 the CERN Council approved the construction of the the highest energies, many current mysteries, such as dark more technologically innovative Intersecting Storage Rings matter and the origin of neutrino masses, may well origi(ISR) over a very high-energy proton synchrotron, although thelatterwouldmaterialise10yearslaterintheSuperProton Synchrotron (SPS). The ISR’s first proton–proton collisions, whichreachedacentre-of-massenergyof62GeV, tookplace on 27 January 1971, opening the era of hadron colliders. From the ISR came the ingenious conversion of the SPS nate from phenomena at energy scales inaccessible to any collider imaginable. Fortunately, models involving such scales can be tested nowandinthenearfuturebya seriesofexperiments–some using magnets from the LHC andHERAinfact–searching for very weakly interacting “slim” particles that arise in extensions of the Stand- ardModel(seep25). Effective fieldtheoryisanotherpower- fultooltopursuesuchsignals fromfarbeyondtheTeVscale, explains Steven Weinberg in this issue’s interview (p51). –into a proton–antiproton collider (SppS), the demonstration of large-scale superconducting magnet technology for the Tevatron at Fermilab, and the LHC, whose elegant magnet design has enabled the highest collision energies (13TeV) and luminosities to date. Each machine, and its increasingly complex detectors, was a step into the unknown, requiring the invention of new technologies and sharp political and organisational skills to build and operate ever larger facil- ities. The payoff was the discovery of the Standard Model’s –cornerstones: the W and Z bosons at the SppS, the top quark at the Tevatron, and the Higgs boson at the LHC. Not to be Discovery machine The LHC. omittedfromthehadron-beamcollidersuccessstoryarethe leapsinunderstandingofstronglyinteractingmatterbrought Meanwhile at CERN: ATLAS reports the first evidence for a Eachmachine, andits increasingly complex detectors, was astepinto the unknown aboutbyBrookhaven’sRelativisticHeavy-IonColliderandthe rare“Dalitz”decayoftheHiggsboson(p17);pulsed-modeantiLHC, andthedeep-inelasticscatteringexperimentsatDESY’s hydrogen paves the way to test antimatter in free fall (p7); and so-faruniqueelectron–protoncolliderHERA, whichrevealed the CLOUD experiment reveals a new mechanism that could <ul style="display: flex;"><li style="flex:1">the proton’s innards in full colour. </li><li style="flex:1">acceleratethelossofArcticseaice(p9).Elsewhereinthisissue: </li></ul>Half a century after the ISR’s first collisions, and with at least quantum sensors target gravitational waves (p10); X-rays go 15 years of LHC operations still to come, particle physicists behindthescenesofsupernova1987A(p12);ahigh-performance once again find themselves debating the next best step for the computing collaboration forms to handle the big-physics data field. True to form, as recommended by the 2020 update of the onslaught (p22); new twists in the ATOMKI tale (p74); and more. Reporting on international high-energy physics <ul style="display: flex;"><li style="flex:1">Editor </li><li style="flex:1">Laboratorycorrespondents </li></ul>Argonne National Laboratory Jefferson Laboratory Kandice Carter JINR Dubna B Starchenko KEK National Laboratory Hajime Hikino Lawrence Berkeley Laboratory Spencer Klein Los Alamos National Lab Rajan Gupta NCSL Ken Kingery Nikhef Robert Fleischer Novosibirsk Institute S Eidelman SLAC National Accelerator Laboratory Melinda Baker SNOLAB Samantha Kuula TRIUMF Laboratory Marcello Pavan Technical illustrator Alison Tovey Advertising sales Tom Houlden Recruitment sales Chris Thomas Advertisement production Katie Graham Marketing and circulation Laura Gillham, Jessica Pratten General distribution CourrierAdressage, CERN, 1211Geneva23, Switzerland; e-mail courrier- CERN Courier is distributed to governments, institutes and laboratories affiliated with CERN, and to individual subscribers. It is published six times per year. The views expressed are not necessarily those of the CERN management. Matthew Chalmers Associate editor Mark Rayner Editorial assistant Craig Edwards Archive contributor Peggie Rimmer Astrowatch contributor Merlin Kole Tom LeCompte Brookhaven National Laboratory Achim Franz Cornell University D G Cassel DESY Laboratory Till Mundzeck <a href="mailto:[email protected]" target="_blank">[email protected] </a>Published by CERN, 1211 Geneva 23, Switzerland Tel +41 (0) 22 767 61 11 Produced for CERN by IOP Publishing Ltd Temple Circus, Temple Way, Bristol BS1 6HG, UK Tel +44 (0)117 929 7481 E-mail <a href="mailto:[email protected]" target="_blank">[email protected] </a>Fermilab Kurt Riesselmann Printed by Warners (Midlands) plc, Bourne, Lincolnshire, UK Forschungszentrum Jülich Markus Buescher GSI Darmstadt I Peter IHEP, Beijing Lijun Guo IHEP, Serpukhov Yu Ryabov Advertising <ul style="display: flex;"><li style="flex:1">Advisory board </li><li style="flex:1">Orsay Laboratory </li></ul>Anne-Marie Lutz PSI Laboratory P-R Kettle Saclay Laboratory Elisabeth Locci Head of Media Jo Allen Head of Media Business Development Ed Jost Content and production manager Ruth Leopold Tel +44 (0)117 930 1026 (for UK/Europe display advertising) or +44 (0)117 930 1164 (for recruitment advertising); e-mail <a href="mailto:[email protected]" target="_blank">[email protected] </a> Peter Jenni, Christine Sutton, Claude Amsler, Philippe Bloch, Roger Forty, Mike Lamont, Joachim Kopp 2021 CERN ©ISSN 0304-288X <ul style="display: flex;"><li style="flex:1">INFN Antonella Varaschin </li><li style="flex:1">UK STFC Jane Binks </li></ul>SWISS OFFICIAL DISTRIBUTOR OF EDWARDS Jambe-Ducommun 19 | 2400 Le Locle | CH +41 32 926 26 06 | [email protected] <a href="/goto?url=http://www.plasmadiam.com" target="_blank">www.plasmadiam.com </a>CERN COURIER MARCH/APRIL 2021 5<a href="/goto?url=http://cerncourier.com" target="_blank">WWW</a><a href="/goto?url=http://cerncourier.com" target="_blank">. </a><a href="/goto?url=http://cerncourier.com" target="_blank">CERN</a><a href="/goto?url=http://cerncourier.com" target="_blank">COURIER </a>V o l u m e 6 1 N u m b e r 2 m a r c h / a p r i l 2 0 2 1 CERNCOURIER.COM NEWS ANALYSIS AntimAtter FOR AEgISontracktotestfreefallofantimatter PROFESSIONALS <ul style="display: flex;"><li style="flex:1">The AEgIS collaboration at CERN’s </li><li style="flex:1">schemeallowsthetimeatwhich90%of </li></ul>theatomsareproducedtobedetermined with an uncertainty of around 100 ns. Further steps are required before the measurement of g can begin, explains Doser. These include the formation of a pulsed beam, greater quantities of antihydrogen, and the ability to make it colder. “Withonlythreemonthsofbeam timethisyear,andlotsofnewequipment to commission, most likely 2022 will be the year in which we establish pulsedbeam formation, which is a prerequisite forustoperformagravitymeasurement.” AntiprotonDecelerator(AD)hasreported a milestone in its bid to measure the gravitational free fall of antimatter – a fundamentaltestoftheweakequivalence principle. Using a series of techniques developed in 2018, the team demon- strated the first pulsed production of antiatoms, which allows the time at which the antiatoms are formed to be knownwithhighaccuracy. Thisisakey step in determining “g” for antimatter. “This is the first time that pulsed formation of antihydrogen has been established on timescales that open the door tosimultaneousmanipulation, bylasers Targeted approach or external fields, of the formed atoms, as well as to the possibility of applying thesamemethodtothepulsedformation ofotherantiprotonicatoms,”saysAEgIS spokesperson Michael Doser of CERN. “Knowing the moment of antihydrogen formation is a powerful tool.” Generalrelativity’sweakequivalence Followingaproof-of-principlemeasurementofgforantihydrogenbytheALPHA collaborationin2013, ALPHA, AEgISand a third AD experiment, GBAR, are all targeting a measurement of g at the 1% level in the coming years. In contrast to AEgIS’s approach, whereby the vertical deviation of a pulsed horizontal beam of coldantihydrogenatomswillbemeasured

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