I NTERNATIONAL J OURNAL OF H IGH -E NERGY P HYSICS CERNCOURIER WELCOME V OLUME 5 4 N UMBER 6 J ULY /A UGUST 2 0 1 4 CERN Courier – digital edition Welcome to the digital edition of the July/August 2014 issue of CERN Courier. In July 1964, the results of an experiment with neutral kaons at Brookhaven Laboratory took particle physicists by surprise when it discovered CP Fifty years of violation – a subtle difference between particles and antiparticles. This issue takes a look at the discovery and some of what followed at CERN. In CP violation particular, the NA31 and NA48 experiments played a leading role in the discovery of direct CP violation, which helped to understand the phenomenon in the context of the Standard Model of particle physics. Fifty years later, interest in the effect shows no sign of abating, especially after CP violation was also found in B mesons at KEK and SLAC in 2001. Experiments to pin down the phenomenon continue, for example, with B mesons at the LHC, and are also beginning to turn to neutrinos. The NOvA experiment at Fermilab has neutrino oscillations in its sights, as well as an initial study of CP violation. To sign up to the new-issue alert, please visit: http://cerncourier.com/cws/sign-up. To subscribe to the magazine, the e-mail new-issue alert, please visit: http://cerncourier.com/cws/how-to-subscribe. FERMILAB EXOTICS BEAMS ARE NOvA takes a new COSY’s new look at neutrino evidence for a BACK EDITOR: CHRISTINE SUTTON, CERN oscillations six-quark state The PS at CERN DIGITAL EDITION CREATED BY JESSE KARJALAINEN/IOP PUBLISHING, UK p30 p6 starts up again p5 CERNCOURIER www. V OLUME 5 4 N UMBER 6 J ULY /A UGUST 2 0 1 4 CERN Courier July/August 2014 Improve Contents Covering current developments in high-energy physics and related fi elds worldwide CERN Courier is distributed to member-state governments, institutes and laboratories affi liated with CERN, and to their personnel. It is published monthly, except for CERNCOURIER Your Crystal Purity January and August. The views expressed are not necessarily those of the CERN management. Editor Christine Sutton V OLUME 5 4 N UMBER 6 J ULY /A UGUST 2 0 1 4 News editor Kate Kahle CERN, 1211 Geneva 23, Switzerland E-mail [email protected] Fax +41 (0) 22 785 0247 5 N EWS Web cerncourier.com • LS1: beams are back in the Proton Synchrotron • ALPHA Advisory board Luis Álvarez-Gaumé, James Gillies, Horst Wenninger experiment measures charge of antihydrogen • COSY confi rms Laboratory correspondents: existence of six-quark states CEBAF delivers fi rst beams Argonne National Laboratory (US) Tom LeCompte • Brookhaven National Laboratory (US) P Yamin following upgrade Laser experiment simulates supernova Cornell University (US) D G Cassel • DESY Laboratory (Germany) Till Mundzeck First direct high-precision measurement of the proton’s EMFCSC (Italy) Anna Cavallini • Enrico Fermi Centre (Italy) Guido Piragino magnetic moment sets the stage for BASE • ALICE and the Fermi National Accelerator Laboratory (US) Katie Yurkewicz fl owing particle zoo Higgs and top: a new window on dark Forschungszentrum Jülich (Germany) Markus Buescher • GSI Darmstadt (Germany) I Peter ± ± BICOM_12710.02 0.06.2014 matter ATLAS fi nds evidence for the rare electroweak W W © IHEP, Beijing (China) Tongzhou Xu • IHEP, Serpukhov (Russia) Yu Ryabov production New results from ATLAS at Quark Matter 2014 INFN (Italy) Romeo Bassoli • Jefferson Laboratory (US) Steven Corneliussen US particle-physics community sets research priorities OECD JINR Dubna (Russia) B Starchenko • • KEK National Laboratory (Japan) Nobukazu Toge report praises innovation at CERN Lawrence Berkeley Laboratory (US) Spencer Klein Los Alamos National Laboratory (US) Rajan Gupta NCSL (US) Ken Kingery 15 S CIENCEWATCH Nikhef (Netherlands) Robert Fleischer Novosibirsk Institute (Russia) S Eidelman Orsay Laboratory (France) Anne-Marie Lutz 17 A STROWATCH PSI Laboratory (Switzerland) P-R Kettle Saclay Laboratory (France) Elisabeth Locci Science and Technology Facilities Council (UK) Julia Maddock 19 A RCHIVE SLAC National Accelerator Laboratory (US) Farnaz Khadem TRIUMF Laboratory (Canada) Marcello Pavan F EATURES Produced for CERN by IOP Publishing Ltd IOP Publishing Ltd, Temple Circus, Temple Way, 21 CP violation’s early days Bristol BS1 6HG, UK Tel +44 (0)117 929 7481 A look back at a surprising discovery 50 years ago. Publisher Susan Curtis Production editor Lisa Gibson 23 NA31/48: the pursuit of direct CP violation ©Photo: with courtesy of K. Pierz, PTB, Germany Technical illustrator Alison Tovey Group advertising manager Chris Thomas Some background to an important result for the Standard Model. Advertisement production Katie Graham Marketing & Circulation Angela Gage 26 What’s next for CP violation? Head of B2B & Marketing Jo Allen Art director Andrew Giaquinto Interest in CP violation continues Cryo pumps for UHV and XHV applications today with studies of b hadrons Advertising Tel +44 (0)117 930 1026 (for UK/Europe display advertising) and neutrinos. or +44 (0)117 930 1164 (for recruitment advertising); Improving the mobility of carriers in a two- E-mail: [email protected]; fax +44 (0)117 930 1178 30 NOvA takes a new look at neutrino oscillations General distribution Courrier Adressage, CERN, 1211 Geneva 23, Switzerland E-mail: [email protected] A new experiment gets going using Fermilab’s upgraded dimensional electron gas (2DEG) in GaAs layers In certain countries, to request copies or to make address changes, contact: neutrino beam. China Keqing Ma, Library, Institute of High Energy Physics, Our wide range of COOLVAC cryo pumps with additional LN cooling PO Box 918, Beijing 100049, People’s Republic of China 2 E-mail: [email protected] 35 F ACES &P LACES Germany Antje Brandes, DESY, Notkestr. 85, 22607 Hamburg, Germany capacity in the radiation shield will allow you to achieve pressures as low E-mail: [email protected] -12 Italy Loredana Rum or Anna Pennacchietti, INFN, Casella Postale 56, 00044 Frascati, ECRUITMENT as 1 x 10 mbar. During the bakeout phase, these cryo pumps can handle Rome, Italy 43 R E-mail: [email protected] the additional thermal load up to 300 °C! This ensures a very effective bakeout UK Mark Wells, Science and Technology Facilities Council, Polaris House, North Star Avenue, Swindon, Wiltshire SN2 1SZ 47 B OOKSHELF resulting in ultra low pressures. E-mail: [email protected] US/Canada Published by Cern Courier, 6N246 Willow Drive, COOLVAC cryo pumps are available in 2000, 3000 and 5000 l/s pumping St Charles, IL 60175, US. Periodical postage paid in St Charles, IL, US 50 V IEWPOINT Fax 630 377 1569. E-mail: [email protected] speed for nitrogen. This family of cryogenic pumps is completed with smart POSTMASTER: send address changes to: Creative Mailing Services, PO Box 1147, St Charles, IL 60174, US I NTERNATIONAL J OURNAL OF H IGH -E NERGY P HYSICS controllers, effi cient cold heads and compressor units. CERNCOURIER Published by European Organization for Nuclear Research, CERN, V OLUME 5 4 N UMBER 6 J ULY /A UGUST 2 0 1 4 1211 Geneva 23, Switzerland Your solution for low-mobility MBE: COOLVAC cryo pumps! COOLVAC 5000 iCL cryo pump Tel +41 (0) 22 767 61 11. Telefax +41 (0) 22 767 65 55 Fifty years of CP violation Printed by Warners (Midlands) plc, Bourne, Lincolnshire, UK Oerlikon Leybold Vacuum GmbH © 2014 CERN ISSN 0304-288X Bonner Strasse 498 On the cover: In the 1980s and 1990s, two experiments at CERN – fi rst NA31 and then NA42 – sent neutral kaons down the long decay tube, visible to the left, in D-50968 Köln studies that led to the discovery of direct CP violation in the particles’ decays (p23). T +49 (0) 221-347-0 FERMILAB EXOTICS BEAMS ARE NOvA takes a new COSY’s new Today, the NA62 experiment follows in their footsteps with investigations of rare look at neutrino evidence for a BACK oscillations six-quark state The PS at CERN F +49 (0) 221-347-1250 p30 p6 starts up again p5 kaon decays.(Image credit: CERN-EX-0304025-03.) [email protected] www.oerlikon.com/leyboldvacuum 3 Anz_LN2 Kryo_CERN_072014.indd 1 11.06.14 12:37 CERNCOURIER www. V OLUME 5 4 N UMBER 6 J ULY /A UGUST 2 0 1 4 CERN Courier July/August 2014 A Member of The Linde Group News CERN LS1: beams are back in the Proton Synchrotron Far left: The PS injection kicker (green signal) sent the fi rst proton bunch into the accelerator on 20 June, for thousands of turns. Beam-position monitors see the bunch every time it completes one turn (purple Our world is cool. signal). (Image credit: CERN.) Left: Jean-Phillipe Tock, the SMACC project leader, adds Linde Kryotechnik. to send beams to the his signature to mark the closure of the last of Beams of protons are back in CERN’s East Area and the neutron facility, nToF, 1695 outer magnet bellows, alongside Luca Proton Synchrotron (PS), having circulated where physics is planned to start in late July. Bottura, group leader of magnets, around the accelerator on 20 June for the ISOLDE, the only experimental facility superconductors and cryostats. (Image fi rst time in more than 15 months. The connected directly to the PSB, will be the credit: CERN-PHOTO-201406-127 – 10.) PS restart followed on from the restart of fi rst user to receive its beams, with physics Creating places colder than deep space, we are extending beam in Linac 2 and then the PS Booster set to restart in mid-July. The physics Sommaire en français the boundaries of knowledge to reveal a new generation (PSB) on 2 June.