Jul/Aug 2014
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.
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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 o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 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 o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 News editor Kate Kahle CERN, 1211 Geneva 23, Switzerland E-mail cern[email protected] Fax +41 (0) 22 785 0247 5 N E W s 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 s t r O W a t C h PSI Laboratory (Switzerland) P-R Kettle Saclay Laboratory (France) Elisabeth Locci Science and Technology Facilities Council (UK) Julia Maddock 19 a r C h i v E SLAC National Accelerator Laboratory (US) Farnaz Khadem TRIUMF Laboratory (Canada) Marcello Pavan F E a t u r E s 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 a C E s &P L a C E s Germany Antje Brandes, DESY, Notkestr. 85, 22607 Hamburg, Germany capacity in the radiation shield will allow you to achieve pressures as low E-mail: desypr@desy.de -12 Italy Loredana Rum or Anna Pennacchietti, INFN, Casella Postale 56, 00044 Frascati, E C r u i t M E N t 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 O O k s h E L F 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 i E W P O i N t 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 o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014
A Member of The Linde Group News
C E r N 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. programme in the Super Proton Synchrotron The beam made it into the PS on schedule, is set to restart in the autumn. LS1: les faisceaux sont de retour dans le 5 of physics. thanks to the efforts of the PSB specialist At the LHc, the teams closed the last of Synchrotron à protons teams, who were called upon on many the 1695 outer magnet bellows on 18 June, occasions for hardware interventions marking the end of the Superconducting L’expérience ALPHA mesure la charge de 5 Linde Kryotechnik – your solution. during the preceding weeks of hardware Magnets And circuits consolidation l’antihydrogène commissioning and “cold” tests. These (SMAcc) project. Leak tests on the entire COSY confi rme l’existence des états à six 6 included fi xing vacuum leaks, re-confi guring machine are proceeding well, and by late quarks timing links, correcting magnet connections June they had been completed in sector 5-6 and, in one instance, replacing an entire and were under way in sector 7-8. At the same CEBAF livre ses premiers faisceaux après 6 magnet with a spare, owing to a water time, sector 6-7 – the fi rst to be cooled – had son relèvement d’énergie leak. operations, radiofrequency and reached 20 K, and will be maintained at this Des faisceaux laser pour simuler une 7 instrumentation teams then needed to temperature during continuity testing of the supernova adjust the settings for beam acceleration copper stabilizer. Four sectors should be cool and extraction from the PSB to the PS. With by the end of the summer, and all eight sectors La première mesure directe de haute 8 beam back in the PS, beam commissioning of the LHc are scheduled to be cooled to the précision du moment magnétique du proton tests could begin. During this fi nal phase, all nominal temperature of 1.9 K in late autumn. ouvre la voie à BASE of the beam diagnostics – from beam current Beam is expected back into the LHc early ALICE et le zoo de particules en mouvement 9 to bunch spacing – need to be checked, fi rst in 2015, and the restart of the LHc physics with low-intensity beams (1011 protons) programme is planned for spring 2015, with Higgs et top : une fenêtre sur la matière noire 9 before moving to higher-intensity levels a collision energy of 13 TeV instead of the ATLAS trouve des indices probants de la 10 12 (10 protons). The PS will then be ready previous 7–8 TeV. production électrofaible de W±W± Nouveaux résultats d’ATLAS à 11 ALPHA measures charge of antihydrogen « Quark Matter 2014 » La communauté de la physique des 12 The ALPHA experiment at cern’s system of particle traps in the presence of particules des États-Unis fi xe des priorités de Antiproton Decelerator (AD) has made a an electric fi eld. If the antihydrogen atoms recherche new precision measurement of the electric had a charge, the fi eld would defl ect them. charge of antihydrogen atoms, fi nding it to The analysis, based on 386 events, gives the Un rapport de l'OCDE fait l'éloge de 13 be compatible with zero to eight decimal value of the antihydrogen electric charge as l'innovation au CERN –8 places. This is the fi rst time that the charge (–1.3±1.1±0.4) × 10 . Dinosaures : ni chauds ni froids 15 of an antiatom has been measured to high precision. The ALPHA collaboration ● Further reading De mystérieux rayons X : la manifestation 17 studied the trajectories of antihydrogen C Amole et al. 2014 Nature Communications 5; d’un neutrino stérile ? Linde Kryotechnik AG atoms released from the experiment’s doi:10.1038/ncomms4955. Daettlikonerstrasse 5, 8422 Pfungen, Switzerland Phone +41.52.3040555, www.linde-kryotechnik.ch 5 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 News News Silicon Drift Detector • Solid State Design • Easy to Use N EW P a r t i C L E s L a B O r a t O r Y astrOPhYsiCs top view • Low Cost 0.2 cm Θn = 83 deg dibaryon I(JP) = 0(3+) Laser experiment optical probe field of view COSY confi rms (interferometry and Schlieren) TM 0 FAST SDD simulates supernova turbulent flow existence of Bx –0.2 carbon rod Count Rate = >1,000,000 CPS
analysing power drive laser Bz By Supernova explosions, triggered when Resolution Peaking Time six-quark states the fuel within a star reignites or its core induction probe 125 eV FWHM 4 µs 2.2 2.4 2.6 2.8 collapses, launch a shock wave that sweeps energy (GeV) shock grid through a few light-years of space in only a 130 eV FWHM 1 µs side view 140 eV FWHM 0.2 µs experiments at the Jülich cooler Energy dependence of the analysing power few hundred years. The remnants of these induction probe Synchrotron (coSY) have found near 90°, where the maximum resonance explosions are now recognized widely as 160 eV FWHM 0.05 µs compelling evidence for a new state in effect occurs. Red symbols show the new Illustration of currently known quark one of nature’s major particle accelerators. grid 1.1 mm2 aperture the two-baryon system, with a mass of measurements, and dashed and solid lines confi gurations. In addition to the standard The theory is that charged particles SDD Spectrum 5.9 2380 MeV, width of 80 MeV and quantum show the SAID partial-wave solution with confi gurations consisting of three valence increase in energy through repeated keV P + 55 numbers i(J ) = 0(3 ). The structure, and without resonance. quarks (baryons) or quark–antiquark pairs encounters with magnetic “mirrors” or Bz Fe 300 J, 527 nm B containing six valence quarks, constitutes (mesons), there is now compelling evidence changing magnetic fi elds in the shocks. 300 μm, 1 ns Bx y eV FWHM
Counts 125 a dibaryon, and could be either an exotic where a deuteron is produced together with for exotic confi gurations. After the recent now, a team of researchers has brought 25 mm2 x 500 µm 6.4 compact particle or a hadronic molecule. a pair of neutral pions (CERN Courier discovery of “tetraquark” systems – mesons some of these processes down to earth, in turbulent flow 11.2 µs peaking time The result answers the long-standing September 2011 p8). now this state has consisting of two quarks and two antiquarks an experiment to investigate the turbulent P/B Ratio: 20000/1 keV question of whether there are more also been observed in polarized neutron– (cern courier June 2014 p12) – the newly amplifi cation of magnetic fi elds in the Energy (keV) eigenstates in the two-baryon system proton scattering and extracted using discovered dibaryon resonance points to supernova remnant, cassiopeia A, which –10 0 10 20 30 distance (mm) Resolution vs Peaking Time than just the deuteron ground-state. This the partial-wave analysis technique – the confi gurations composed of six quarks. was fi rst seen about 300 years ago in the 180 2 fundamental question has been awaiting generally accepted ultimate method to (Image credit: IKP-FZJ.) constellation cassiopeia. Top: Diagram of the experiment with the 25 mm 170 an answer since at least 1964, when fi rst reveal a resonance. in the SAiD partial-wave radio observations of cassiopeia A have grid in place. Bottom: Schlieren image at Freeman Dyson and later robert Jaffe analysis, the inclusion of the new data Garcilazo reproduce the features of this new revealed regions within the expanding 300 ns after the laser shot. 160 Standard SDD 3 envisaged the possible existence of produces a pole in the D3 partial wave at state very well. The quantum numbers favour remnant that are consistent with synchrotron TM non-trivial six-quark confi gurations. (2380 ± 10 – i 40±5) MeV. this state as a dibaryon resonance – the radiation emission from giga-electron-volt scaling, the wire thickness corresponds to a 150 FAST SDD distance of about one parsec in the remnant. The new resonance was observed in The mass of the new state is amazingly “inevitable” non-strange dibaryon predicted electrons spiralling in a magnetic fi eld 140 high-precision measurements carried out close to that predicted originally by Dyson, by Terry Goldman and colleagues in 1989. of a few milligauss – 100 times higher The researchers used various techniques by the WASA-at-coSY collaboration. based on Su(6) symmetry breaking. than expected from the standard shock to monitor the evolution of the shock 130 The fi rst signals of the new state had been Moreover, recent state-of-the-art Faddeev ● Further reading compression of the interstellar medium. The wave, including an induction coil to Resolution (eV FWHM @ 5.9 keV) 120 seen before in neutron–proton collisions, calculations by Avraham Gal and Humberto P Adlarson et al. 2014 Phys. Rev. Lett. 112 202301. origin of such high magnetic fi elds, which measure the magnetic fi elds produced. 0 1 2 3 4 5 Peaking Time (μs) help to make cassiopeia A a particularly The measurements show that the grid J E F F E r s O N L a B effective particle accelerator and bright produces additional turbulent fl ow and Throughput radio source, appears to lie with regions gives rise to magnetic-fi eld components 1,00,0000 CEBAF delivers fi rst beams following upgrade of turbulence that could amplify the that are 2–3 times larger than without it. magnetic fi eld and that could be related to The results are also in good agreement with 0.2 μs puzzling irregular “knots” seen in optical the output from numerical simulation code, 100,000 1 μs on 7 May, the newly upgraded continuous in May 2012, the accelerator was shut observations. one explanation for these knots in particular, the magnetohydrodynamic electron Beam Accelerator Facility down for its 12 GeV upgrade (CERN Courier is that the shock produces turbulence as it code FLASH, developed by Don Lamb 4 μs (CEBAF) delivered the fi rst electron november 2012 p30). This $338-million passes through a region of space that already at chicago university. The simulations 10,000 beams to its new experimental complex at project, which will double ceBAF’s contains dense clumps or clouds of gas. reproduce well the position of the shock, the uS Department of energy’s (Doe’s) maximum energy, includes the construction To investigate these possibilities, an the peak electron density and temperature – Rate (OCR) Output Count Jefferson Lab. The success capped a string of a fourth experimental hall (Hall D), as well international team led by Gianluca Gregori with and without the grid – and confi rm that 1,000 1,000 10,000 100,000 1,000,0000 of accelerator commissioning milestones as upgrades to equipment in three existing at oxford university used the Vulcan laser the magnetic fi eld is indeed enhanced as a Input Count Rate (ICR) that were needed for approval to restart halls (Halls A, B and c) (CERN Courier On 7 May, operators successfully threaded facility at the uK’s rutherford Appleton result of induced turbulence created as the experimental operations following ceBAF’s April 2009 p15). the fi rst electron beam up the new beamline Laboratory to focus three laser beams onto a shock moves through the grid. fi rst major upgrade. Accelerator operators began the towards Hall D. (Image credit: Jefferson Lab.) carbon rod 0.5 mm thick in a chamber fi lled These results demonstrate that the ceBAF is an electron-accelerator painstaking task of bringing the accelerator with low-density gas. The heat generated amplifi cation of the magnetic fi eld within facility that employs superconducting back online last December. By 5 February, energy was increased to 10.5 GeV through made the rod explode, creating a blast that the cassiopeia A “particle accelerator” radiofrequency (SrF) technology to they had achieved the full upgrade-energy the entire 5.5 passes. in the last minutes of the expanded through the surrounding gas, might indeed arise from the interaction investigate the quark structure of the nucleus. acceleration of 2.2 GeV in one pass through day, 10.5 GeV beam was delivered into the mimicking a supernova shock wave. To of the shock with a clumpy interstellar The fi rst large-scale application of SRF the machine. Then on 1 April, the operators new Hall D complex. Having met all of the simulate the clumps that might surround an medium. importantly, the experiment technology in the uS, it was originally built exceeded ceBAF’s previous maximum major milestones in the 12-GeV project for exploding star, the team introduced a mesh also gives valuable confi rmation of to circulate electrons through 1–5 passes to energy. The accelerator delivered three-pass, the Doe approval step, critical Decision-4A of fi ne plastic wires 0.4 mm thick with cells the simulations, providing for the fi rst provide 4 GeV electron beams. As a result 6.11-GeV electron beams with 2 nA average (Accelerator Project completion and Start 1.1 mm square at a distance of 1 cm from time an experimental means to validate Please see our web site for of the operators’ experience in running the current onto a target in Hall A, and recorded of operations), staff and users are now the rod. using hydrodynamical scaling the simulation codes used for many machine at its peak potential, the original the fi rst data of the 12-GeV era, holding the looking forward to demonstration of 12-GeV relations, the team can relate the experimental astrophysical phenomena. complete specifications and installation eventually achieved operational pattern for more than an hour. energy and beam delivery to Jefferson Lab’s conditions 0.3 μs after the laser burst to vacuum applications energies of 6 GeV (CERN Courier october The operators continued to push the experimental halls for commissioning and the cassiopeia A as it is now, about 310 years ● Further reading 2000 p9). upgraded machine, and early on 7 May the start of experiments. after the supernova explosion. With the same J Meinecke et al. 2014 Nature Physics 10 520. AMPTEK Inc. [email protected] www.amptek.com 6 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 News News
F u N D a M E N t a L P h Y s i C s L h C P h Y s i C s First direct high-precision measurement of the ALICE and the fl owing particle zoo
proton’s magnetic moment sets the stage for BASE relativistic heavy-ion collisions 0.4 —− produce large numbers of centrality: 10–20% centrality: 40–50% ALICE Pb-Pb√sNN = 2.76 TeV particles that do not move 0.3 π± K A German/Japanese collaboration working precision trap individually, but rather as
at the university of Mainz has performed the an organized group, with a | > 0.9) p + p φ fi rst direct high-precision measurement of analysis trap collective motion known as fl ow. Flow η 0.2 | Δ – + the magnetic moment of the proton – which is studies at Brookhaven’s relativistic P, Λ + Λ Ξ + Ξ
(S 0.1 2
by far the most accurate to date. The result is Heavy-ion collider (rHic) contributed v – + + consistent with the currently accepted value to the surprising realization that the hot Ω Ω 0 of the committee on Data for Science and and dense matter created in the collisions Technology (coDATA), but is 2.5 times more behaves like a perfect liquid and not as a 0 2 4 6 0 2 4 6 precise and 760 times more accurate than any hadron gas. now, the ALice collaboration pT(GeV/c) pT(GeV/c) previous direct measurement. The techniques at the LHc has looked further into how these magnetic 1.89T used will feature in the Baryon-Antibaryon field effects vary for different particle species. The pT-differential v2 for different particle species, represented by the different symbols and Symmetry experiment (BASe) – recently 1.17T in relativistic heavy-ion collisions the colours, for the 10–20% (left plot) and the 40–50% (middle plot) centrality intervals of approved to run at cern’s Antiproton collective motion, or fl ow, is governed by PbPb collisions at √sNN = 2.76 TeV. Decelerator (AD) – which aims at the direct Fig. 1. The double Penning trap set-up used the spatial anisotropy of the almond-shaped high-precision measurement of the magnetic to measure the proton magnetic moment 60 overlap region of the colliding nuclei and Radial fl ow tends to create a depletion in different particle species within the same moments of the proton and the antiproton with with an unprecedented precision of 3.3 parts 50 the initial density inhomogeneities of the the particle pT spectrum at low values, which centrality interval in central (left plot) and fractional precisions at the parts-per-billion in a billion. (Image credit: Georg Schneider.) 40 fi reball. These features are transformed, increases with increasing particle mass and peripheral (middle plot) PbPb collisions. (ppb) level, or better. through interactions between the produced transverse velocity. When introduced in a A clear mass ordering is seen for 30 Prior to this work, the record for the most of the proton μp is obtained fi nally in units of particles, into an anisotropy in momentum system that exhibits azimuthal anisotropy, this all centralities in the low-pT region precise measurement of the proton’s magnetic the nuclear magneton, μp/μn = νL/νc. 20 space. The degree of this transformation depletion becomes larger along the shorter (i.e. pT ≤ 2 G eV/c). comparisons with moment had stood for more than 40 years. This approach has already been applied 10 depends on the ratio of shear viscosity to axis of the anisotropy, thereby reducing v2. hydrodynamic calculations in this spin flip probability (%) in 1972, a group at Massachusetts institute with great success in measurements of the entropy, η/s, which quantifi es the friction of The net result is that at a fi xed value of pT, transverse-momentum range indicate that the of Technology measured its value indirectly magnetic moments of the electron and the 0 the created matter. This resulting anisotropy heavier particles have a smaller value of produced matter at the LHc seems to favour by performing ground-state hyperfi ne positron. However, the magnetic moment –60 –40 –20 0 20 40 60 in particle production can be quantifi ed v2 than lighter ones. in the intermediate pT a value of η/s smaller than twice the quantum 9 spectroscopy with a hydrogen maser in a of the proton is about 660 times smaller g/gCODATA–1(parts per 10 ) by a Fourier analysis of the azimuthal region (2 < pT < 5 GeV/c), the v2 of baryons is mechanical limit. in the intermediate pT magnetic fi eld. This experiment measured the than that of the electron, so the proton distribution relative to the system’s larger than that of mesons. This phenomenon region (pT > 2 GeV/c), although the particles ratio of the magnetic moments of the proton measurement requires an apparatus that is Fig. 2. The measured g value normalized to symmetry plane, characterized by Fourier was conjectured to originate within a picture tend to group according to their type (i.e. and the electron. The results, combined with orders of magnitude more sensitive. To detect the currently accepted value gCODATA. The c o e f fi c i e n t s , v n. The second harmonic, v2, is where fl ow develops at the partonic level mesons and baryons), the ncQ scaling, if theoretical corrections and two additional the proton’s spin state, the collaboration used solid line is a maximum-likelihood fi t to the known as the elliptic-fl ow coeffi cient. and quarks coalesce into hadrons during any, is only approximate. in particular, the independent measurements, enabled the an extremely strong magnetic inhomogeneity data, avoiding the need for data binning. The one of the major outcomes from rHic hadronization. The proposed mechanism φ-meson, with a mass close to that of p and calculation of the proton magnetic moment of 300,000 T/m2. However, this limits the shaded area indicates the 1σ confi dence was the measurement of the elliptic fl ow of was argued to lead to the observed hierarchy Λ, seems to follow the baryon band in central with a precision of about 10 parts in a billion. experimental precision in the frequency band. Binned data points with 1σ error bars identifi ed particles. These results led to the in the fl ow values – the so-called number of events and shifts progressively to the band of in an attempt to surpass the record, the measurements to the parts-per-million (ppm) are shown for visualization and do not enter conclusion that the matter created acts as a constituent quarks (ncQ) scaling. mesons for peripheral collisions. This seems collaboration of scientists from Mainz level. Therefore a second trap – the precision the line fi t explicitly. It took about four system where the value of η/s is very close The ALICE collaboration, profi ting to indicate that the mass, rather than the university, the Max Planck institute trap – was added about 45 mm away from the months to record the entire set of 450 data to the lower bound of ħ/4πkB conjectured from the unique particle-identifi cation number of constituent quarks, is the driving for nuclear Physics in Heidelberg, GSi strong magnetic-fi eld inhomogeneity. In this points. (Image credit: Andreas Mooser.) within anti-de Sitter/conformal fi eld theory capabilities that the detector set-up provides, force of the v2 evolution with pT also in the Darmstadt and the Japanese riKen institute trap the magnetic fi eld is about 75,000 times – i.e. a nearly perfect liquid. At low values of had measured v2 in PbPb collisions at intermediate region. applied the so-called double Penning trap more homogeneous than in the analysis trap. technique will be applied directly to a single transverse momentum (pT), for pT < 2 GeV/c, √snn = 2.76 TeV for different centrality technique to a single proton for the fi rst To determine the magnetic moment of trapped antiproton and will potentially the experiments found an interesting intervals and various particles: π, K, p, Λ, ● Further reading – – 0 time (see fi gure 1). One Penning trap – the proton, the fi rst step was to identify improve the currently accepted value of mass-ordering of v2(pT), attributed to the Ξ , Ω (and their antiparticles), Ks and φ. B B Abelev et al. (ALICE Collaboration) 2014 called the analysis trap – is used for the the spin state of the single particle in the the magnetic moment by at least a factor interplay between elliptic and radial fl ow. The fi gure illustrates how v2 develops for arXiv:1405.4632 [nucl-ex]. non-destructive detection of the spin state, analysis trap. Afterwards the particle was of 1000. This will constitute a stringent through the continuous Stern-Gerlach effect. transported to the precision trap, where the test with baryons of cPT symmetry – the in this elegant approach, a strong magnetic cyclotron frequency was measured and a most fundamental symmetry underlying Higgs and top: a new window on dark matter inhomogeneity is superimposed on the trap, spin fl ip induced. Subsequently the particle the quantum fi eld theories of the Standard so coupling the particle’s spin-magnetic- was transported back to the analysis trap Model of particle physics. cPT invariance moment to its axial oscillation frequency in and the spin state was analysed again. By implies the exact equality of the properties With the discovery of a neutral and colourless particles, χ, with mass was to exploit their elastic scattering on the trap. By measuring the axial frequency, repeating this procedure several hundred of matter–antimatter conjugates and any Higgs boson at the LHc two ranging from a few to a few hundred giga- nuclei inside sensitive detectors, working the spin quantum state of the trapped particle times, the magnetic moment was measured measured difference could contribute to years ago, the last piece of electron-volts. The LHc, with its high-energy typically at low temperatures. These can be determined. And by recording in the homogeneous magnetic fi eld of the understanding the striking imbalance the Standard Model puzzle collisions, provides an excellent pace to search direct-detection experiments aim to observe the quantum-jump rate as a function of a precision trap. The result, extracted from the of matter and antimatter observed on fell into place. Yet, several for such particles, and the cMS collaboration the scattering by measuring the momentum spin-fl ip drive frequency, the spin precession normalized resonance curve (fi gure 2), is the cosmological scales. mysteries remain, one of which is the enigma has been taking a new look at ways in which of the recoiling nucleus. While interesting frequency νL is obtained. Together with a value μp = 2.792847350(9)μn, with a relative of the origin of dark matter. one of the most they could be produced. hints for dark-matter detection in various ● Further reading measurement of the cyclotron frequency νc precision of 3.3 ppb. popular classes of models predicts that the until recently, the main experimental mass ranges have been reported by some of ▲ of the trapped particle, the magnetic moment in the BASe experiment at the AD the A Mooser et al. 2014 Nature 509 596. dark matter is made of weakly interacting method to look for dark-matter particles these experiments, none of these hints
8 9 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 News News
to enrico Fermi’s effective theory of muon particularly rare and diffi cult to detect. Standard Model processes is reduced by signifi cance of 3.6σ. The measured fi ducial − –1 √s = 8 TeV, L = 19.7 fb –1 decay, where the messenger – a W boson – is The ATLAS collaboration has presented using the fact that these processes rarely cross-section is 1.3±0.4 fb, in agreement 10 combination of VBF and
CMS preliminary (pb) CMS observed 95% CL ZH,_ H → invisible much heavier than the muon. the fi rst evidence of this rare process produce two leptons with the same electric with the Standard Model expectation of –N 150 median expected –3 √s = 8.0 TeV, L = 18.9–19.7 fb–1(VBF+ZH) χ
SI _ 10 –1 Another interesting way to look for dark involving a quartic WWWW interaction in a charge, together with the knowledge that the 0.95±0.06 fb, and provides the fi rst step expected +– 1σ √s = 7.0 TeV, L = 4.9 fb (ZH) + B(H inv) < 0.51 @ 90% CL (GeV) expected – 2σ → matter is based on precision measurements of paper submitted to Physical Review Letters. quarks that recoil off the radiated W bosons into a previously untouched segment of the ATLAS observed limits (90% CL) –5 mH = 125 GeV * 10 100 the properties of the Higgs boson. if the mass The ATLAS analysis selected events with will produce jets that are separated widely Standard Model. 10–7 of the dark-matter particle is less than roughly two same-charge W bosons (reconstructed and have a particularly large invariant mass. scalar half of the Higgs boson mass, for instance, through their leptonic decays to electron or Data collected by the ATLAS experiment ● Further reading –9 CRESST 1σ 10 CRESST 2σ Mχ < 60 GeV, then it is possible to look for a muon and their respective (anti)neutrinos) show an excess of these events across the ATLAS Collaboration 2014 submitted to Phys. Rev. 50 fermion XENON100(2012) nominal limit of min XENON10(2011) Lett. arXiv:1405.6241. EFT validity –11 DAMA/LIBRA direct decay of the Higgs boson into a χχ pair. and two jets. The background from other predicted background, with a statistical lower limits on M vector CoGeNT(2013)/90%CL 10 lattice CoGeNT(2013)/99%CL max CDMS(2013)/95%CL This decay is called “invisible” because its COUPP(2012) –13 LUX(90%CL) 0 DM-nucleon cross-section σ 10 products are not detected. C O N F E r E N C E 2 3 1 10 10 10 10 102 103 The cMS collaboration recently Mχ (GeV) DM mass Mχ (GeV) published a search for such invisible Higgs-boson decays, where the production New results from ATLAS at Quark Matter 2014 Fig. 1. Left: Limits on the dark-matter particle mass as a function of the effective of the Higgs is tagged either by the presence interaction scale from the associated production of the particle with a top-quark pair. of a Z boson (associated ZH production), Fig. 2. Right: The limits set on the dark-matter particle mass from the search for invisible or by the presence of two forward jets, At the Quark Matter 2014 conference, (a) Higgs-boson decays compared with those from direct-detection experiments. characteristic of vector-boson fusion (cMS held in Darmstadt on 19–25 May, ATLAS (b) centrality 0-70%, no q selection centrality 0–70%, no q selection 0.05 2 collaboration 2014b). The upper limits set presented a variety of new results based on 2 ATLAS preliminary 0.3 ATLAS preliminary have been confi rmed by later, more precise these searches have been extended to more on the invisible branching fraction of the lead–lead (PbPb) and proton–lead (pPb) √sNN = 2.76 TeV √sNN = 2.76 TeV –1 Lint = 7 μb , Pb + Pb measurements. complicated signatures, for example the Higgs boson are 51% and 58% at a 90% and data collected during run 1 of the LHc. The –1 Lint = 7 μb , Pb + Pb 0.04 Several years ago, a new idea appeared: to production of dark matter in association 95% confi dence level, respectively. The PbPb results included new measurements 0.2 < 2 GeV) < 4 GeV) T look for the production of pairs of dark-matter with a pair of top quarks, which are former limit can be translated to limits on of event-by-event correlations and T particles in high-energy particle collisions, produced in abundance at the LHc. The the mass of the dark-matter particle vs its fl uctuations of collective fl ow, high-statistics centrality intervals 0.03 with q selection: (3 < p 2 like those at the LHc, via a process described new analysis looks for top-quark pairs that interaction cross-section with a nucleon, measurements of photon and W production, 2 0.1 (0.5 < p
v 0–5% 30–35% 3
by the same Feynman diagram as the are recoiling against a large amount of which allows for a direct comparison and studies of jet quenching using charged 10–15% 40–45% v 20–25% 50–55% 0.02 scattering of the dark-matter particles on “missing” transverse momentum, carried with the limits coming from various particles, single jets, nearby jet pairs and 60–65% quarks inside the nuclei, but “rotated” by 90°. away by dark-matter particles. direct-detection experiments, as fi gure 2 jet-fragmentation functions. The results from 0 While such direct-detection experiments look As fi gure 1 shows, a new measurement shows. The limits are set for various types pPb data included precision measurements 0 0.05 0.10 0.15 0 0.05 0.10 0.15 v (0.5 < p < 2 GeV) v (0.5 < p < 2 GeV) for the process qχ → qχ, experiments at the by cMS of the production of top-quark of dark-matter particle: scalar, vector, or a of long-range pseudorapidity correlation and 2 T 2 T – LHc can look for qq → χχ. The challenge is to pairs in association with missing transverse Majorana fermion. They are signifi cantly associated azimuthal structures, and high-pT trigger on these events, because dark-matter momentum sets stringent limits in the plane more stringent than the direct-detection production of charged particles, Z bosons Fig.2. Correlation of (a) v2 in two different pT –1 ATLAS preliminary anti-kt, R = 0.4 jets 2011 Pb + Pb data, Lint = 0.14 nb particles would leave no trace in the detector. of the dark-matter particle mass Mχ vs an limits for low masses for dark matter, and jets. Here are some of the highlights. –1 ranges, and (b) v and v in the same p √sNN = 2.76 TeV 2013 pp data, Lint = 4.0 pb 3 2 T one possibility is to search for a more effective interaction energy scale, M* (cMS emphasizing the complementarity Following the fi rst observation of highly 1.0 range. The data points in each centrality AA
complicated process, where an additional collaboration 2014a). The interaction of dark of the searches by the LHc and the asymmetric dijets in PbPb collisions, R interval correspond to the 14 event classes particle, for example a gluon or a photon, is matter with the known particles is usually direct-detection experiments. the study of jet quenching has been an 0.5 with different ellipticity selected via an |y| < 2.1 produced together with the dark matter. assumed to be carried by new “messenger” essential part of the heavy-ion physics 0 event-shape engineering technique. The The cMS experiment has performed a particles. if the messengers are heavy – ● Further reading programme at the LHc. Measurements 1006040 200 400 data are overlaid with the centrality number of such searches, which are referred which would be a good reason why they have CMS Collaboration 2014a PAS B2G-13-004: https:// of the production of electroweak bosons pT (GeV) dependence without event-shape selection to collectively as mono-X searches, because not yet been seen – the interaction can be cds.cern.ch/record/1697173?ln=en. provide important control data for the study (thick line). they look for a single object, X, recoiling approximated via a point-like interaction with CMS Collaboration 2014b submitted to EPJC, of jet quenching, as well as for investigating Fig.1. The modifi cation of jet yields, against the invisible particles. recently, an effective energy scale of M*. This is similar arXiv:1404.1344. nuclear modifi cations to parton distribution quantifi ed by the nuclear modifi cation forward pseudorapidity. The correlation in functions. ATLAS presented new results on factor, RAA, as a function of jet pT for three v2 for two different ranges in pT (fi gure 2(a)) the measurement of W-boson production via centrality bins: 0–10% (red circles), shows non-trivial centrality dependence ATLAS fi nds evidence for the rare q qʹ the electron and muon decay modes in PbPb 30–40% (blue squares) and 60–80% (green but is linear within a narrow centrality + ± ± W collisions at √snn = 2.76 TeV, with yields of diamonds). interval. This linearity indicates that viscous electroweak W W production W bosons obtained as a function of centrality effects are controlled by the size of the and pseudorapidity. A good agreement was presented the most precise measurement of jet system, and not its overall shape. The v3–v2 found between the two decay channels. The suppression to date. in central collisions, the correlations, shown in fi gure 2(b), reveal The Standard Model WWγγ. The other boson combinations are yields are in agreement with the predictions jet yields are suppressed by more than a factor a surprising anticorrelation between the of particle physics forbidden on symmetry grounds. now the based on modifi ed next-to-leading- of two below a jet transverse momentum, ellipticity and triangularity of the initial W+ has been extremely ATLAS collaboration has found evidence for order calculations, while leading-order pT, of around 150 GeV (see fi gure 1), but the geometry, which is not accessible via the successful in a process involving the fi rst of these three – q qʹ calculations underestimate the yield. suppression is found to be reduced at higher pT. traditional measurements. The v4–v2 and predicting a vast variety of phenomena – so the WWWW interaction. Jets produced in heavy-ion collisions can ATLAS presented fi rst results on v5–v2 correlations provide the most direct successful, that it is easy to forget that some The WWWW and WWZZ interactions, in Representative Feynman diagram for the interact with the medium that is produced direct correlations between the elliptic and detailed picture of the interplay between of its predictions have not yet been verifi ed. particular, are of great theoretical interest. if WWWW quartic-gauge interaction at the in the collisions and lose energy through the fl ow coeffi cient, v2, and higher-order the linear and nonlinear collective dynamics A very important one, related intimately to there were no Higgs boson, the rate of these LHC. phenomenon of jet quenching. This energy fl ow harmonics, v3, v4 and v5, in PbPb in the fi nal state of the PbPb collisions. electroweak symmetry breaking, is that the processes would become unphysically large. loss suppresses the rate of jets produced in collisions. This correlation is obtained via Turning to the pPb runs, the large data gauge bosons (γ, W and Z) can interact with With the discovery of a Higgs boson, they the LHc, the WWWW interactions can be these collisions, relative to proton–proton an event-shape engineering technique, in sample collected at √snn = 5.02 TeV in each other through quartic interactions. Four have remained interesting as a way to study studied through the radiation of W bosons collisions, where no such effects are present. which events within the same centrality 2013 allowed ATLAS to measure the jet
such interactions are allowed in the Standard electroweak symmetry breaking and even from quarks (see fi gure). This is a rare using the high-statistics proton–proton data interval are divided into different classes production over the widest kinematic range ▲ Model: WWWW, WWZZ, WWZγ and to probe for new heavier Higgs bosons. At process, making the interaction of W bosons set from 2013 as the new reference, ATLAS according to the observed ellipticity in the ever probed in proton–nucleus collisions.
10 11 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 News News
s O C i E t Y 1.4 ATLAS rec Ldt = 27.8 nb–1 ATLAS preliminary 220 <_ Nch < 260 complete accelerator-system design in 1999 of cern, which allows it to “recyle” its preliminary ∫ b 1 < p T < 3 GeV, ⏐Δη⏐>2 —– –1 OECD report praises (CERN Courier october 1998 p20). cern’s infrastructure for new projects, and the p+Pb √sNN = 5.02 TeV 0.15 Lint ≈ 28 nb n=2 1.0 p+Pb n=3 involvement in hadron therapy is also a story cern staff. This manpower is described as anti-kt, R = 0.4 n=4 n=5 innovation at CERN of collaboration – the laboratory retains close a “great asset” for the organization, which
CP 0–10% off n
R 0.10 CMS, 220<_Ntrk <260 * * V can be deployed in response to strategic “top +3.6 < y < +4.4 +0.3 < y < +0.8 off links with cnAo, the national centre for v2, Ntrk <20 sub. +2.8 < y* < +3.6 –0.3 < y* < +0.3 off oncological Hadron Therapy in italy, and down” decisions or in response to initiatives v3, Ntrk <20 sub. 0.4 * * +2.1 < y < +2.8 –0.8 < y < –0.3 0.05 in early June, the organisation for economic the MedAustron centre in Austria and others that arise in a “bottom up” mode. * * +1.2 < y < +2.1 –1.2 < y < –0.8 co-operation and Development (oecD) (CERN Courier December 2011 p37). ● For the full report, see www.oecd.org/sti/ +0.8 < y* < +1.2 –2.1 < y* < –1.2 0 published their Global Science Forum (GSF) The report also praises the longevity sci-tech/cern-case-studies.pdf. 40 100 1000 40 100 1000 0 5 10 report, “The impacts of Large research * a PT × cosh(
for the future of the country’s particle physics. neutrinos, dark matter, dark energy and LBnF. The facility would use a neutrino project stemmed from cern, contractors le - Photo: Scott Maxwell, Master www.agence-arca.com Top priorities in the plan – written by the infl ation, and as-yet-undiscovered particles, beam at Fermilab, upgraded through interviewed for the study reported their Particle Physics Prioritization Panel (P5) – interactions and physical principles. it the proposed project called the Proton experience with the organization to be include continuing to play a major role at the advises increasing investment in the improvement Plan ii, together with a positive. CERN’s fl exibility and ability LHc in europe; building a world-leading construction of new experimental facilities. massive liquid-argon neutrino detector to innovate attracts creative, ambitious neutrino programme hosted in the uS; and The P5 panel envisions the uS as the placed underground, probably at the Sanford individuals, such that “success breeds success participating in the development of a proposed host of an international programme of underground research Facility in South in innovation”, note the report’s authors. future linear collider, if a decision is made in neutrino research that will operate the Dakota, and a smaller detector placed nearer The second case study covered cern’s Japan to go forward with construction. world’s most powerful neutrino beam to the source of the beam. contribution to hadron therapy using beams The P5 report culminates a process open and, with international partners, build The plan emphasizes the need for the uS of protons, or heavier nuclei such as carbon, to to all members of the uS particle-physics a major long-baseline neutrino facility to begin several planned second-generation kill tumours. The authors attribute cern’s community that lasted more than a year. it complemented by multiple small, dark-matter experiments immediately, success in pushing through medical research
was presented to the High energy Physics short-baseline neutrino experiments. with a vision to build at least one large, to its relatively “fl at” hierarchy, where Pantone 286 Pantone 032 Advisory Panel (HePAP), a body that Launching this programme will involve third-generation experiment in the uS students and junior members of staff can formally advises the uS Department of a change in direction, because the panel near the beginning of the next decade. it share ideas freely with heads of department Energy Offi ce of Science and the National recommends reformulating the currently also recommends increasing funding for or management. A key project was the Science Foundation. planned Long-Baseline neutrino the particle-physics components of cosmic three-year Proton ion Medical Machine Magnetic precision has a name www.metrolab.com The plan recommends a uS experiment as an internationally designed, surveys. Study, which started in 1996 and submitted a
12 13 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 ampegon.com Sciencewatch
C OMPILED BY J OHN S WAIN , N ORTHEASTERN U NIVERSITY Dinosaurs: neither hot nor cold
There has been much debate whether Dinosaurs and some living animals are dinosaurs were cold-blooded ectotherms, mesotherms, raising but not maintaining like modern reptiles, or warm-blooded their body temperature. (Image credit: endotherms, like most modern mammals. adapted from Grady et al./Illustration Greg However, they might have been neither, Harris.) according to the bold suggestion that has been put forward by John Grady of the allowed the dinosaurs to outcompete sluggish university of new Mexico and colleagues. exotherms, and crowd out the large-animal By plotting (in a mass-independent manner) niches, preventing endotherms from growth rate as a function of metabolic rate for becoming bigger and ruling the earth – at nearly 400 living and extinct animals (using least until an asteroid hit. Modern mesotherms known scaling laws and annual bone rings to that dinosaurs were likely to have been what are few, but include tuna and the echidna. obtain dinosaur growth rates), the researchers they call mesotherms – a class of animal that fi nd that dinosaurs lie in-between the can raise its body temperature, but does not ● Further reading exotherms and endotherms. They wpropose maintain it at a specifi c level. This would have J M Grady et al. 2014 Science 344 1268.
Life, but not as we know it Storage institute of the Agency for Science Self-repairing plastic Technology and research in Singapore and The genetic code of all natural organisms colleagues used spontaneous parametric is expressed in terms of the pairs A-T and Self-repair is common in living organisms, but down-conversion of 266-nm nd:YAG laser G-c – the letters representing pairs of is now also possible in plastics. S R White of pulses to generate photon pairs, directing complementary bases in DnA that code for the University of Illinois at Urbana-Champaign one to a retinal rod cell from a Xenopus the 20 amino acids from which all proteins and colleagues have developed plastics with laevis toad, while using the other as a trigger. are made. now, Denis Malyshev of the biomimetic vascular networks of capillaries Without the need for the statistical modelling Scripps research institute and colleagues fi lled with two liquids. These materials, when used in previous studies, they fi nd solid have persuaded living bacteria to accept a punctured, allow the liquids to ooze out, mixing proof of single-photon sensitivity, with a third pair: d5SicS and dnAM – call them X to form a gel that plugs the hole and later quantum effi ciency of 29±4.7%. This is close Expertise of a Century and Y. Both the DnA and rnA can hold the polymerizes into a robust fi ller, repairing the to estimates for human rod cells obtained extra X-Y pairs and the bacteria – if provided damage. Holes more than 35 mm in diameter earlier from behavioural experiments. Innovation, advanced technology and premium quality systems with X and Y, which they cannot synthesize fi ll within 20 minutes, with mechanical function themselves (they would die outside the lab restored within 3 hours with 62% of the original ● Further reading environment) – can reproduce with the new material performance. N M Phan et al. 2014 Phys. Rev. Lett. 112 213601. code. The new letters do not code for anything «Our unique technical expertise in the fi eld of scientifi c, medical and industrial yet, but this allows, in principle, for 172 amino ● Further reading Did Ötzi come from Sardinia? applications positions us to develop and realise future market demands.» acids, and vastly increases the variety of S R White et al. 2014 Science 344 620. proteins that could be produced. The work An analysis of the genome of Ötzi, the Wolfgang Kaesler and Günter Böhm, Managing Directors of Ampegon PPT could also help to shed light on why the bases 5300 year-old Tyrolean “iceman”, has used by the life we know are what they are. species on which it climbs. Mimicry in plants, yielded interesting insights into the origins or “crypsis”, has been seen before, but only via of the well-preserved mummy found near ● Further reading taking on an appearance that is similar to a the Austrian–italian border in 1991. Martin D A Malyshev et al. 2014 Nature 509 385. background or colour pattern, or looking like Sikora of Stanford university and colleagues one single plant, so this is a record. have found that his Y-chromosome lineage Visit Ampegon at FEL 2014 Booth 1 Plant mimicry is one found almost only in corsica and ● Further reading Sardinia, and is rare elsewhere in europe. Mimicry is common in the animal world, but E Gianoli et al. 2014 Current Biology 24 984. using in addition genomic data from ernesto Gianoli and Fernando carrasco-urra modern Sardinians and ancient europeans of the universidad de concepción have The quantum eye from other geographic regions, the team also found that the woody climbing vine Boquila suggests that the Ötzi’s Sardinian ancestry trifoliolata, which grows in the temperate Folk wisdom has it that the eye is sensitive is shared with individuals associated with Ampegon AG South American rainforest, can vary nine around the single-photon level, but so far all the beginning of agriculture during the Spinnereistrasse 5 | CH-5300 Turgi, Switzerland features of its leaves, including size, shape, studies have been done with sources with neolithic period, and the transition away Tel. +41 58 710 44 00 | Fax +41 58 710 44 01 and colour. This allows it to mimic any of classical photon statistics, such as lamps, from hunter-gatherer life in europe. [email protected] | ampegon.com 12 other species – possibly to help it avoid LeDs, lasers, etc. it is therefore interesting herbivores. A single plant can even change the to see what does actually happen with single ● Further reading Ampegon PPT GmbH shape of its leaves as the vine moves between photons. Leonid Krivistky of the Data M Sikora et al. 2014 PLOS Genetics 10 e1004353. Feldstrasse 56 | D-44141 Dortmund, Germany Tel. +49 231 476459 0 | Fax +49 231 476459 77 Transmission Antenna Scientifi c Green [email protected] | ampegon.com Systems Systems Applications Technologies 15 Transmission Antenna Scientifi c Green Systems Systems Applications Technologies cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 Astrowatch
C OMPILED BY M ARC TÜRLER , ISDC AND O BSERVATORY OF THE U NIVERSITY OF G ENEVA , AND U NIVERSITY OF Z URICH Do X-rays reveal a sterile neutrino?
A detailed study of galaxy clusters using What makes many researchers doubt the nASA’s chandra X-ray observatory and results, is that the intensity of the emission eSA’s XMM-newton has found a mysterious line is signifi cantly different from one cluster X-ray signal. one intriguing possibility is to the other. While the detection in the full that the X-rays are produced by the decay of sample of clusters corresponds to a mixing sterile neutrinos – a candidate particle for angle for the decay that is below previously dark matter – although there is doubt that this determined upper limits, the line in Perseus is the correct interpretation. is much brighter than expected for this The mystery surrounds an unidentifi ed mixing angle (based on the cluster’s mass X-ray emission line at energy and distance), deviating signifi cantly from e = 3.56±0.03 keV, found in the Perseus other subsamples. The fact that the detected galaxy cluster, during a study of data from signal is very weak (with an equivalent width both the chandra and XMM-newton in the full sample of about 1 eV only) and missions led by esra Bulbul from located within 50–110 eV of several known WEKA AG · Switzerland the Harvard-Smithsonian center for faint lines is also suspicious. However, the Schürlistrasse 8 · CH-8344 Bäretswil Astrophysics. The team also found the line authors recognize that “the dark matter Phone +41 43 833 43 43 in a combined study of 73 other galaxy A new study of the Perseus galaxy cluster, explanation is a long shot” and that they Fax +41 43 833 43 49 clusters observed with XMM-newton. As shown in this image, and others using “have a lot of work to do before they can
Visual Level Indicators Visual Level Instruments Tank Cryogenic Components Stainless Steel Valves these clusters have different redshifts, this Chandra and XMM-Newton, has revealed a claim, with any confi dence, that they have [email protected] · www.weka-ag.ch fi nding excludes, a priori, the possibility mysterious X-ray signal in the data, which found sterile neutrinos”. ARCA Flow Group worldwide: that the line is an instrumental artifact. The might be from sterile neutrino decay. (Image This study on a possible dark-matter Competence in valves, pumps & cryogenics authors of the study admit, however, that credit: Chandra: NASA/CXC/SAO/E.Bulbul signal follows the report on the excess of the detection is at the limit of the current et al.; XMM-Newton: ESA.) gamma-ray emission from the Galactic instrumental capabilities. centre observed with Fermi, which The researchers argue that there should The paper on these fi ndings was submitted strengthened the case for a signal from C@™º¬™Ñ™º|® E®ÑźÆ@™¬ÅØ be no atomic transitions in thermal plasma to The Astrophysical Journal in February and annihilating dark matter (CERN Courier at this energy. They therefore suggest that posted on the arXiv preprint server, igniting a April 2014 p13). in this case, it is still early ä ä this emission line could be a signature from fl urry of activity, with 60 new papers having days. Have the researchers stumbled on HV Power Supplies RF Amplifiers the decay of a sterile neutrino with a mass cited this work in the four months from something really interesting? Future studies ä Water Cooling ä of ms = 2e = 7.1 keV. Sterile neutrinos are a March to June. Some of these papers explore and better instrumentation are needed to Integrated Control hypothetical type of neutrino predicted to the sterile neutrino interpretation, while settle the issue. Systems Systems interact with normal matter via gravity only. others suggest that other types of candidate They have been put forward as candidates to dark-matter particles, such as axions, might ● Further reading explain dark matter, at least partially. have been detected. E Bulbul et al. 2014 ApJ 789 13.
Picture of the month
This colorful image of the Whirlpool Galaxy is a composite of X-ray observations (in purple) from the Chandra X-ray Observatory superimposed on the optical image from the Hubble Space Telescope. With more than 10 days of overall observing time, Chandra revealed about 500 X-ray sources in Providing Custom Solutions for Science,Communications Defense and this beautiful spiral galaxy, also known as Messier 51 (CERN for over 65 years Courier July/August 2010 p14). Most of these sources are X-ray binaries consisting of pairs of objects where a compact star, either a neutron star or a black hole, is capturing material from an orbiting companion star. The infalling material is accelerated by the intense gravitational fi eld of the compact star and heated to millions of degrees, producing a luminous Complete Systems X-ray source. The more diffuse, or fuzzy, X-ray emission in this interacting galaxy comes from gas that has been Contact: heated to multi-million degrees by supernova explosions of Paul Utayor Mike Troje massive stars. (Image credit: X-ray: NASA/CXC/Wesleyan 800.733.5011• (1)214.381.7161 Univ./R Kilgard et al.; optical: NASA/STScI.) [email protected] • www.contelec.com Solid State Cavity Amplifiers Power Supplies
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p16.indd 1 02/07/2014 13:13 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier Archive: 1971 VERIFY AND OPTIMIZE YOUR DESIGNS WITH A LOOK BACK TO CERN C OURIER VOL . 11, A UGUST 1971, COMPILED BY P EGGIE R IMMER ® COMSOL MULTIPHYSICS C E r N i i Heisenberg’s principles RF COUPLER: This model computes the transmission probability through an RF coupler using both the angular coefficient method available in the Free Molecular Flow interface and a Monte Carlo remote from the noise and bustle of Werner Heisenberg: at the expense of their national effort – even if method using the Mathematical Particle Tracing interface. europe’s capital cities, in the charming thoughts on big it were to mean closing a national laboratory. German lakeside town of Lindau close to the machines. it is rare to see demands on the State purse Multiphysics tools let you build simulations borders of Austria and Switzerland, nobel accompanied by proposals that require that accurately replicate the important prize winners in physics gathered from June sacrifi ces by those making the demand. characteristics of your designs. The key is the 28–July 2 to talk of their science and its Dispassionate advice ability to include all physical effects that exist interaction with society. The fi rst of these annual meetings one acute problem facing governments was in the real world. of nobel prize winners was a medical the question of cost and relative value had to their dependence on scientists for advice. in congress in 1951. This year’s assembly was enter into consideration. a fi eld as restricted as high-energy physics, To learn more about COMSOL Multiphysics, 21st in the series and seventh where the There was a question mark too over the the advisers are inevitably interested parties visit www.comsol.com/introvideo main theme was physics. type of discoveries that can be made at higher and a sacrifi ce is necessary as a proof of readers of the CERN Courier would energies. it could be that there is no longer good faith, to convince the politicians of the have been particularly interested in the subdivision of matter, but only the creation of genuineness of their submissions. The uK conference given by Professor Heisenberg new particles or new particle states. cosmic physicists had done so. in which he analysed his past and present ray evidence had not suggested that there was undoubtedly, the formation of an attitudes to the Super Proton Synchrotron anything more fundamental to be found. international community is to be encouraged project [for a 300 GeV machine, approved in any case, the iSr should reveal and its institutions and centres supported.
© Copyright 2013-2014 COMSOL in February 1971 to be built in a new any basically new phenomena and if Happily, cern is one of the best examples laboratory adjacent to cern Lab i]. He conventional machines of higher energy of international collaboration but several was reputed at one time to be strongly were then shown to be necessary, one should others, such as Trieste, lspra, Grenoble and opposed to the project, the eminence fi rst consider new techniques so that they the various space centres are all contributing. grise in German science discouraging could be built more cheaply. The question of the location of these participation. certainly in a number of centres is, however, also important, and interviews he made clear his reservations Competing claims a reasonable distribution across europe about the early proposals, but reports on At the level of expenditure, sums need to be is indispensable. it had been hoped that You know what his views were sometimes tendentious and diverted from other activities and if a new the German site of Drensteinfurt would even, one suspects, apocryphal. Here was synchrotron is built collectively this is also a be selected for the 300 GeV machine but you want to detect: an opportunity to hear how Heisenberg’s drain on the national pools of assets. choices the cost reductions associated with the thoughts had evolved and what new of this nature are disagreeable – particularly proposition for cern Lab ll shifted the considerations led to his approbation. when trying to balance the quest for balance in favour of this second choice. The - X-rays Among the points he raised was the fundamental knowledge against day-to-day stability afforded to the present laboratory fact that when projects of the size and problems. national defence raises even more was also a valuable element and insured - Gamma-rays signifi cance of the 300 GeV machine are in diffi culties; money forthcoming from that against a future over-provision of facilities in question, it is naïve to believe that politics direction must be made available by those this domain and consequently an excessive - Neutrons can be ignored. The scale of expenditure, responsible for the defence. production of physicists. Taking all these choice of location and relevant urgency The uK made a positive contribution aspects into consideration, the compromise - Particles are all matters where public discussion is towards resolving this argument by agreeing solution of cern Lab ll is a good one. Untitled-1 1 necessary and public31/01/2014 policy, 09:57 i.e. politics, is to participate in the new cern programme ● compiled from texts on pp221–222. involved. First the physics Compiler’s Note From the physics angle, previous experience Werner Heisenberg died some four months before John Adams would suggest that larger machines – higher announced to the June 1976 Council meeting that the Super Proton energies – would yield new information Synchrotron (SPS) had accelerated protons to 300 GeV. Adams there and new knowledge. Moreover, the fi eld and then sought and obtained Council’s approval to increase the energy of elementary particle physics concerns to 400 GeV. Five minutes later, he reported that 400 GeV protons were physics at its most fundamental, the circulating in the machine. Contrary to Heisenberg’s supposition, laws of nature to which all physical laws can be reduced. At the same time, the the Intersecting Storage Rings (ISR) did not make any major physics SCIONIX Holland B.V. technological stimulus created by this work breakthroughs, but did launch CERN’s outstanding hadron-collider Tel. +31 30 6570312 at the frontiers of knowledge is of general programme, which is approaching a zenith as the LHC prepares to deliver Fax. +31 30 6567563 We know how to importance. Such arguments certainly were 13 TeV proton–proton collisions, with the indefatigable SPS as the fi nal in favour of the construction of a machine of accelerator in the pre-injection chain. Email. [email protected] build your detectors www.scionix.nl 100 GeV or so, but for still higher energies
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p18.indd 1 02/07/2014 13:36 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 Anniversary Temperature is our business CP violation’s early days Mineral Insulated Cable Reliable, Highly accurate cabling capable of A brief look back at a discovery that surprised operating in extreme environments. the world of particle physics 50 years ago.
MgO and SiO2 Cables. RF Coaxial Cables. Multiconductor Transmission Cables. in the summer of 1964, at the international conference on High- Welded and hermetically sealed connections. energy Physics (icHeP) in Dubna, Jim cronin presented the results Capable of operating in and measuring temperatures of an experiment studying neutral kaons at Brookhaven national of up to 1,260oC. Laboratory. in particular, it had shown that the long-lived neutral Capable of operating in the following atmospheres - kaon can decay into two pions, which implied the violation of cP oxidising, reducing, neutral and vacuum. symmetry – a discovery that took the physics community by sur- prise. The news was greeted with some scepticism and met a barrage of questions. Everyone wanted to be satisfi ed that nothing had been overlooked, and that all other possibilities had been considered care- The experiment that discovered CP violation at Brookhaven was fully and ruled out. People need not have worried. cronin, together set up in a neutral beamline, directed inside the ring of the Innovation at Okazaki: Cabling, Temperature Sensors & Heaters | okazaki-mfg.com with Val Fitch, visiting French physicist rené Turlay and graduate Alternating Gradient Synchrotron. Visible here are the two student Jim christenson, had spent months asking themselves the spectrometer magnets positioned at 22° to the beam. Spark CERN_125x193:Mise en page 1 18/09/12 17:17 Page 1 same questions, testing and cross-checking their results thoroughly. chambers tracked particles before and after the magnets. (Image There was, in the end, only one conclusion that they could draw credit: Brookhaven National Laboratory.) okazaki-cernad-193x125-Apr14.indd 1 06/03/2014 10:03 from their observations: cP symmetry was not a perfect symmetry of nature. Only when the researchers were completely satisfi ed did physics do indeed allow absolute distinctions between left- and right- they make their fi ndings known to the physics community. It is tes- handed co-ordinate systems, between particles and antiparticles, and tament to their patience and the quality of their work that the result between time running forwards and backwards. was so robust to scrutiny. it was 15 years later that cronin and Fitch By the early 1960s, the neutral kaon system had already proved to www.goodfellow.com received the 1980 nobel Prize in Physics for the discovery. be a rich testing ground for new physics. its “strange” behaviour had The announcement of a broken symmetry was not new to the been a matter for scrutiny since its discovery in cosmic rays in 1946. physics community, having fi rst occurred only a few years previ- neutral kaons were found to be produced copiously through the ously, when the maximal non-conservation of parity (P) in the weak strong interaction, while their long lifetimes suggested decays via the interaction was discovered by chien-Shiung Wu and her colleagues weak interaction. in 1953, Murray Gell-Mann assigned the K0 a Metals in 1957, following the proposal by Tsung-Dao Lee and chen-ning “strangeness” quantum number, S = 1, which was conserved by the Yang that parity violation might explain puzzles in the decays of strong force but not by the weak force. This implied that there must charged kaons. The disturbing conclusion that the laws of physics exist a distinct anti-K0, K0, with S = –1. However, because both the K0 and materials depend on the frame of reference was evaded, however, because and K0 appeared to decay to two pions, the distinction between the experiments soon showed that symmetry under charge-conjugation particles was blurred somewhat. The situation prompted Gell-Mann for research (c) was also maximally violated. Therefore, as long as the combined and Abraham Pais to propose, in 1955, that the states of defi nite mass operation, cP, was a good symmetry, the possibility of an absolute and lifetime, labelled K1 and K2, were instead an admixture of the distinction between left-handed and right-handed co-ordinate sys- two particles, and were even and odd, respectively, under the cP
Goodfellow Cambridge Limited ON-LINE CATALOGUE tems would be prevented, being compensated exactly by the asym- transformation. under the assumption of cP invariance, the K2 was Ermine Business Park metry between particles and antiparticles. cP invariance had already forbidden to decay to two pions. This gave it a much longer lifetime Huntingdon PE29 6WR UK been suggested as the means to restore symmetry conservation by than the K1, as observed. Tel: 0800 731 4653 or +44 1480 424 800 Lev Landau, and by Lee and Yang, so the situation seemed to be The primary motivation for the experiment at Brookhaven was Fax: 0800 328 7689 or +44 1480 424 900 resolved neatly. to study a phenomenon peculiar to the kaon system called regen- [email protected] When the news came in 1964 that cP was also a broken sym- eration (see box, p22). Fitch, an expert on kaons, had approached metry, it was harder to accept, because no elegant alternative was cronin, who with christenson and Turlay had built a state-of-the- available to replace cP invariance. There was also the issue of the art spectrometer based on spark chambers, which could be oper- treasured cPT theorem: if cPT holds, then cP violation implies ated with an electronic trigger to select rare events. it was just what violation of time-reversal (T) symmetry. The discovery of cP vio- was needed for further tests of regeneration. Finding a “new upper
70 000 PRODUCTS SMALL QUANTITIES FAST DELIVERY CUSTOM MADE ITEMS ▲ lation led to the unsettling conclusion that the microscopic laws of limit” for K2 decaying to 2π was a secondary consideration, listed
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p20.indd 1 02/07/2014 13:39 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Anniversary 60 years of CERN
under “other results to be obtained”. The experiment was approved for 200 hours of run-time, and about half of this was devoted to the Neutral kaon mixing, oscillations and “CP invariance run”, across fi ve days towards the end of June 1963. regeneration Turlay began the analysis of the cP run in the autumn. By the time it was complete, early in 1964, it was clear that 2π decays were pre- Because the weak interaction does not conserve strangeness, second-order weak-interaction processes mediate transitions between sent, with 45±10 events, corresponding to about one in 500 of K2 decays to charged modes. in the conclusion of their seminal paper, the strangeness eigenstates K0 and K0 . Therefore, the physical particles published in July 1964, the team stated: “The presence of a two-pion (eigenstates of mass and lifetime) are linear combinations of K0 and K0 , and states born as one or the other “oscillate” between these two decay mode implies that the K2 meson is not a pure eigenstate of cP” (christenson et al. 1964). eigenstates before decaying. The two physical eigenstates are called KS The NA48 experiment at CERN’s Super Proton Synchrotron, which followed NA31 in the 1990s. From right to left: the target for the
During the year that followed, there was feverish activity in both and KL – short and long – refl ecting their different lifetimes. Allowed to production the KS beam (in the blue frame) followed by the multicoloured fi nal collimator; the almost 120-m-long evacuated decay the experimental and theoretical communities. The discovery of cP propagate for long enough, a mixed beam of neutral kaons will evolve into tube; the liquid krypton calorimeter – new for NA48 and key to detecting the decays to neutral pions. (Image credits, right to left: 0 0 violation raised many questions about its origins, and the size of a pure beam of KL. Because K and K have different interactions with CERN-EX-9610003-07, CERN-EX-9610003-05, CERN-EX-9610003-04.) 0 the effect. in particular, it was unclear from experiment whether the matter, if an initially pure KL beam enters matter, the K component will effect was occurring in the kaon decays (direct cP violation) or in interact preferentially, forming a different admixture of K0 and K0 . This neutral kaon mixing (indirect cP violation). indeed, the results could admixture must be different from the pure KL that entered the matter, be explained solely by invoking indirect cP violation, which was which means that a component of KS is “regenerated” in the beam. Regeneration is not an effect of CP violation, but it is used extensively in NA31/48: the pursuit of achieved by the simple, but ad hoc, addition of a small admixture of the cP = +1 eigenstate to the mass eigenstate of the long-lived neutral “regenerators” in kaon experiments. kaon. This was parameterized by the small complex parameter ε, which had a magnitude of about 2 × 10 –3. The two states of distinct (short and long) lifetime were then K = K + εK and K = K + εK chamber (HLBc), in which the photons from the π0 decays would direct CP violation S 1 2 L 2 1 (to order ε2). convert. First results from the spark-chamber experiments seemed
Among the many theoretical papers that followed in the wake of to indicate that |η 00| was much larger than |η+–|. However, in late 1968 the discovery of cP violation was that by Lincoln Wolfenstein in the HLBc collaboration presented a result that was compatible with η August 1964, which proposed the “superweak” model. This was the |η00| = | +–|. After some confusion, the spark-chamber experiments Over two decades, two experiments at CERN CP violation, ε´, was nonzero. However, considerable theoretical minimal model, which accounted for the observed effect by adding confi rmed this result and also measured φ00. uncertainty remained concerning its value, which was potentially a single CP-violating contribution to the ΔS = 2 mixing-matrix ele- More refi ned experiments were to follow, giving more precise proved the existence of a subtle difference too small to be measured by the existing experimental techniques. ment between the K0 and the K0. There was no cP-violating contri- measurements for the different decay modes. By the time of the This provided fresh impetus to the search for direct cP violation, bution to the kaon decays themselves, hence the model offered a 13th icHeP in London in 1974 – 10 years after the announcement between particles and antiparticles. and prompted renewed efforts at cern and at Fermilab to meet prediction that the phenomenon would be seen only as a feature of in Dubna – all results agreed perfectly with the predictions of the the experimental challenges involved. neutral kaon mixing. Alternatively, a “milliweak” theory would superweak model, with no need for direct cP violation. However, At cern, the nA31 experiment was proposed in 1982 with the include direct cP-violating contributions to neutral kaon decays a new theory that accounted for cP violation was already in the air in 1973 – almost 10 years after the surprising dis- explicit goal of establishing whether the ratio ε´/ε was nonzero. This
(ΔS = 1), as well as to the kaon mixing-matrix element. Another pro- – and with it new challenges for a new generation of experiments. covery of cP violation – Makoto Kobayashi and required measuring all four decay rates of KS and KL to the charged posal was that the action of an all-pervading long-range vector fi eld Toshihide Maskawa produced the fi rst theory of the and neutral 2π fi nal states (see box, p24). The concept behind NA31 ● of cosmological origin could cause the observed decay to 2π without Further reading phenomenon in the context of the Standard Model. was to measure KS and KL decays at the same locations (binned in invoking cP violation. This was a relatively easy option to test exper- J H Christenson et al. 1964 Phys. Rev. Lett. 13 138. They proposed a bold generalization of a mechanism that Sheldon momentum) to provide essentially the same acceptance for each set imentally, because it predicted that the decay rate would depend on J W Cronin 1993 Nishina Memorial Lecture. Glashow, John iliopoulos and Luciano Maiani had put forward in of events, and so reduce the dependence on Monte carlo simula-
the energy of the kaons. 1970. The “GiM mechanism” suppressed strangeness-changing tion. The experiment employed a mobile KS target, able to move The experimental confi rmation of the π+π– decay of the long-lived Résumé weak neutral currents through the introduction of a fourth quark along a 50-m track, with data-taking stations every 1.2 m. Addi- kaon came early in 1965, from groups at the rutherford Laboratory Les débuts de la violation de CP – charm – and was, in turn, an extension of ideas that began with tionally, beam and detector fl uctuations were limited by rapidly
in the uK and at cern. These experiments also dispensed swiftly nicola cabibbo (CERN Courier September 2013 p53). Kobayashi alternating the data-taking between KS and KL. The experimental with the vector-fi eld proposal. There was no evidence for the varia- À l’été 1964, les résultats d’une expérience étudiant les kaons neutres and Maskawa introduced a third generation of quarks (b and t), limitations were determined by statistics and background suppres- tion of the decay rate with energy. experiments were now needed to au laboratoire Brookhaven ont pris par surprise la communauté and a full 3 × 3 unitary matrix parameterizing complex couplings sion. in both cases, a liquid argon calorimeter was used to achieve
determine the cP-violating parameters η+– and η 00 – the ratios of the de la physique des particules. En particulier, cette expérience avait between the quark-mass eigenstates and the charged weak gauge the stable, high-quality energy and position resolution that was + – 0 0 ± 0 0 amplitudes for the KL and KS decays into π π or π π , respectively montré que le kaon neutre à durée de vie longue peut se désintégrer bosons (W ). in this model, a single complex phase in the matrix crucial for reconstructing the π π decays. The calorimeter was (see box p24) – the measurable quantities being the related magni- en deux pions, ce qui implique la violation de la symétrie de CP, donc accounted for all observed cP-violating effects in the kaon system, developed by exploiting the expertise acquired by the group of
tudes (|η+–|, |η 00|) and phases (φ+–, φ00). une subtile différence entre les particules et les antiparticules. Cette and provided for cP violation in matrix elements, both for mixing Bill Willis at CERN with the fi rst liquid-argon calorimeter at the in 1964, Jack Steinberger had realized that the interference découverte a soulevé de nombreuses questions concernant l’origine and for decays – that is, for both indirect and direct cP violation. intersecting Storage rings. + – between KS and KL decaying to the same fi nal state (π π ) could pro- et la dimension de ce phénomène. Des expériences plus affi nées ont The discovery of the b quark in 1977 brought the theory of In 1988, NA31 found the fi rst evidence for direct CP violation, with vide a valuable way to study cP violation. results published in 1966 suivi, donnant des mesures plus précises pour les différents modes de Kobayashi and Maskawa well and truly into the spotlight, and the a result that was about three standard deviations from zero. How- from two such experiments at cern’s Proton Synchrotron provided désintégration. L’article retrace brièvement ce qui a suivi au cours de hunt began to search for the predicted cP violation in the b-quark ever, shortly after this the e731 experiment at Fermilab reported a
measurements of |η+–| and φ+–. The more diffi cult challenge of meas- la décennie suivante, jusqu’à l’été 1974. system (p26). in kaon physics, the crucial experimental ques- measurement that was consistent with zero. These confl icting results uring decays to π0π0 was taken up by spark-chamber experiments at tion now was to disprove the superweak model for cP violation increased the importance of answering the question on the existence cern, Brookhaven and Berkeley. in another experiment at cern, Theresa Harrison, University of Warwick. With thanks to Donald Cundy and (p22), which had no need for direct cP violation. in contrast, in of direct cP violation, and prompted the design of a new generation ▲
a beam of KL passed along a pipe through the Heavy-Liquid Bubble Italo Mannelli. the Kobayashi-Maskawa model, the parameter describing direct of detectors, both at cern (nA48) and at Fermilab (KTeV).
22 23 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 60 years of CERN Inc.
superior performance. powerful technology. Measuring direct CP violation in the neutral-kaon system
CP violation in general manifests itself as a difference between the ® behaviours of particles and antiparticles (apart from the obvious charge SuperPower 2G HTS Wire Second-Generation (2G) High Temperature Superconductor (HTS) – provides advantages of high inversion). In the original experiment at Brookhaven, the observation of current density, superior in-field performance, and high mechanical strength for various electrical and electromagnetic applications the decay of a KL to two pions could be explained by one effect or by a combination of two effects: long, robust lengths with variations in . . . • width (2, 3, 4, 6 and 12 mm) The K is an exact eigenstate of CP with eigenvalue –1. Its decay Members of NA31 – many of whom also took part in NA48 – L • Hastelloy®C-276 substrate thickness (30, 50 and 100 µm) is• mediated by an interaction that violates CP, allowing it to decay gathered at CERN to celebrate the award of the 2005 EPS • silver or silver/gold overlayer (2-6 µm) and copper stabilizer thickness (10-120 µm High-Energy Particle Physics Prize for having shown, for the to a CP = +1 fi nal state (e.g. two pions). Such direct CP violation is total thickness), thicker copper available with clad product fi rst time, direct CP violation in the decays of neutral kaons. parameterized by a complex quantity, ε´. • 2 HTS formulations (AP or CF) for device-specific operating conditions . . . as well as uniform I over long lengths with optional insulation or 2D uniformity (Image credit: CERN-GE-0510038-01.) The KL eigenstate is an admixture of CP = –1 and CP = +1 components, c • (across width) the CP = +1 part being a (complex) fraction ε of the total. This is the case if The nA48 experiment was designed to handle a 10-fold increase the mixing amplitude (which causes transitions between K0 and K0 ) in beam intensity and event rates compared with nA31. it incor- violates CP. This is called indirect CP violation. porated a magnetic spectrometer to reduce background in the The parameter ε measures the admixture of the CP = +1 eigenstate charged-pion mode and a new calorimeter to replace the liquid- in the KL mass eigenstate, so if this were the only source of CP violation, argon original. The novel liquid-krypton calorimeter was fully lon- the fraction of KL decays with a two-pion fi nal state normalized to Ks gitudinally integrating, and had fi ne granularity in two dimensions would be independent of whether the two pions were π+π– or a π0π0. Any Contact us today about our Quick Ship program to provide faster detection with superior resolution for neutral-pion observed difference between the amplitude ratios η+– and η00 would Offering expert engineering & coil winding services decays. Systematic effects were also greatly reduced in nA48 by be evidence for direct CP violation, and the deviation from unity of their squared-ratio (which depends on the respective event rates) can be 450 Duane Ave. . Schenectady, NY 12304 . USA observing all four decay modes concurrently. Tel: 518-346-1414 . Fax: 518-346-6080 in 1999, both the KTeV and nA48 experiments were suc- shown to be six times the real part of ε´/ε. This is given experimentally www.superpower-inc.com . [email protected] cessful in measuring direct cP violation in the decay of neutral by the ratio-of-ratios of event rates. Therefore, to make a measurement kaons, clearly establishing that cP violation was not just con- of the direct CP violation parameter, the four rates must be measured. fi ned to kaon mixing (CERN Courier September 1999 p32). The Because ε´/ε is of the order of 10–3, the measurements are particularly discovery was later recognized by honours in both europe and diffi cult. the uS. in 2005, the european Physical Society’s High-energy Physics Prize was awarded jointly to cern’s Heinrich Wahl, Advancing Cryogenics for his “outstanding leadership of challenging experiments on Blois in 1989, which celebrated the 25th anniversary of the dis- cP violation”, and to the nA31 collaboration as a whole, for hav- covery of the unexpected effect. He described broken symme- ing shown, for the fi rst time, direct CP violation in the decays of try as “something more intriguing and perhaps more beautiful neutral K mesons. Wahl, who was spokesman of nA31, had a than perfect symmetry”. Another 25 years on, that sentiment is long association with cP-violation experiments since his arrival stronger than ever. at cern in 1969, and was also a major proponent of nA48. Two years later, italo Mannelli, Wahl and Bruce Winstein, leader of Résumé the KTeV collaboration, were awarded the W K H Panofsky prize NA31/NA48 : à la recherche de la violation de CP directe of the American Physical Society, in recognition of their “leader- ship in the series of experiments that resulted in a multitude of En 1973, Makoto Kobayashi et Toshihide Maskawa produisaient la Control and Measurement for Cryogenic Applications precision measurements of properties of neutral K mesons, most première théorie de la violation de CP dans le contexte du Modèle Trusted for accuracy and performance in high-profile research programs, from the notably the discovery of direct cP violation”. standard. Avec une troisième génération de quarks, ce modèle CERN particle accelerator to the James Webb Space Telescope, Lake Shore’s precision During the past 50 years, the study of the neutral-kaon system prévoyait une violation de CP aussi bien dans le mélange de kaons temperature sensors and instruments are the world standard for reliable control and has gone hand-in-hand with the development of the Standard neutres (violation de CP indirecte) que dans leurs désintégrations measurement of cryogenic applications. Model. in particular, cP violation in neutral kaons provided the (violation de CP directe). Cette avancée a incité à redoubler With our patented Cernox™ sensors, DT-670 diode sensors, and full range of controllers experimental stimulus for Kobayashi and Maskawa to propose d’efforts dans la recherche de la violation de CP directe, encore and monitors, Lake Shore continues a tradition of innovation and support, with the right the third generation of quarks. That boosted the motivation to jamais observée alors. Au CERN, l’expérience NA31 a trouvé la tools for advancing your research. search for direct cP violation, which in turn motivated improve- première trace de ce phénomène en 1988. Dix ans plus tard, NA48, ments in experimental techniques. The search for direct cP l’expérience qui a pris la suite de NA31, établissait clairement violation across several generations of experiments led to the la violation directe de CP dans les kaons neutres, ce qui devait Temperature Sensors Controllers Monitors tantalizing hint of a result in nA31, before the effect was eventu- conduire à l’attribution de prix internationaux aux physiciens qui ally nailed down by KTeV and nA48. ont travaillé sur ces deux expériences. <20 mK to over 1500 K Models for all applications From 1 to 12 points Cernox, diodes, and specialty types High resolution and reliability Panel and rack mount Victor Hugo wrote in Les Misérables: “La symétrie, c’est Robust packaging Easy to use 4 to 20 mA transmitters l’ennui”. A less succinct but more poetic sentiment was expressed Theresa Harrison, University of Warwick. With thanks to Donald Cundy and NIST-traceable calibrations 3-year warranty on all Lake Shore Compatible with Cernox, diodes, by Wolfenstein at the conference on cP violation at chateau de Italo Mannelli. 614.891.2243 | www.lakeshore.com products and most sensors
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p25.indd 1 02/07/2014 13:42 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Flavour physics Flavour physics What’s next for CP violation?
Fifty years after the discovery of CP violation, 200 160 interest in differences between the behaviour of 120 matter and antimatter shows no sign of abating. 80
number of papers 40 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 The observation of CP violation was fi rst revealed to an unsuspecting
physics community in July 1964 (p21). Since then, as fi gure 1 shows, 1.5 excluded at CL > 0.95 excluded area has CL > 0.95 interest in this puzzling phenomenon has grown signifi cantly. So what is driving this interest and what remains to be studied? γ 1.0 m & m One reason that the fi eld remains so vibrant is the connection Δ d Δ s with the existence of our matter-dominated universe. As Andrei sin 2β Sakharov showed in 1967, the absolute distinction between matter 0.5 Δmd α and antimatter provided by c and cP violation is – together with εK γ β – baryon number violation and a period of thermal inequilibrium – η 0.0 α one of the necessary conditions to generate a net baryon asymme- α ⎢Vub ⎢ try from an initially symmetrical state (Sakharov 1967). Moreover, –0.5 because the Standard Model provides only a small amount of cP violation, and also constrains strongly the amount of baryon num- ε –1.0 γ K ber violation and the phase transitions that cause inequilibrium, it sol. w/ cos 2β < 0 cannot account for the amount of matter surviving the almost total (excl. at CL > 0.95) annihilation that must have occurred in the early universe. This –1.5 –1.0 –0.5 0.0 0.5 1.0 1.5 2.0 mystery strikes a chord among scientists and the general public ρ– alike, because it points to a way to search for physics beyond the Standard Model and hints at a connection to one of the biggest Top: Fig. 1. Growth of interest in CP violation from discovery to questions in science: why is there something rather than nothing? modern day, as measured by journal paper titles containing Although answers to such grandiose questions are by their nature “CP violation” or “CP invariance” (from INSPIRE records by elusive, there has been signifi cant progress in understanding CP publication year). Above: Fig. 2. Constraints on the parameters violation during the past 50 years, and there are excellent prospects The LHC provides a copious source of b hadrons, which the LHCb experiment, in particular, is designed to exploit. Here, the beam pipe is seen of the CKM unitarity triangle, as compiled by the CKMfi tter for further advances. Perhaps the two most important experimental passing through the experiment’s dipole magnet. (Image credit: CERN-PHOTO-0807022 – 01.) group (http://ckmfi tter.in2p3.fr/). results in the fi eld, since the discovery, occurred around the turn of the millenium, corresponding to the peak in fi gure 1. The fi rst the preferred solution being a high-luminosity asymmetrical e+e– the angle β of the cabibbo-Kobayashi-Maskawa (cKM) unitarity allowed several further milestones in cP-violation studies to be was the long-sought observation of direct cP violation through the collider, with a detector equipped with a silicon vertex detector triangle, which represents in the complex plane the relation achieved. one notable result is the observation of direct cP viola- 0 measurement of a nonzero value of the parameter Re(ε'/εK) of the and particle-identifi cation capability. By colliding electrons and VudVub* + VcdVcb* + VtdVtb* = 0 between elements of the cKM quark- tion in B →Kπ decays (CERN Courier September 2004 p5). Fur- neutral kaon system (see p23). The second was the discovery of cP positrons at the centre-of-mass energy of the ϒ(4S) meson, the mixing matrix. other measurements of the properties (angles and ther advances have become possible more recently because an even violation in the B system. facilities could exploit the resonant production of quantum entan- sides) of this triangle are all consistent, as fi gure 2 shows, where the more copious source of b hadrons has become available – the LHc – The model introduced by Makoto Kobayashi and Toshihide gled B–B meson pairs, while the decay vertices of the two parti- constraints all overlap at the apex of the triangle. This astonishing at cern. in particular, the LHcb experiment is designed to exploit Maskawa predicted that cP-violation effects should occur also in cles could be separated owing to the beam-energy asymmetry. agreement between data and theory led to the award of the 2008 the potential for heavy-fl avour physics at the LHC by instrument- the B sector (Kobayashi and Maskawa 1973). Specifically, as Two such “B factories” were built – the PeP-ii and KeKB accel- nobel Prize in Physics to Kobayashi and Maskawa. ing the forward region of proton–proton collisions, and therefore ikaros Bigi, Ashton carter and Tony Sanda showed, a potentially erators, with their associated detectors BaBar and Belle, at SLAc The data represented in fi gure 2 are the result of enormous effor t optimizing the acceptance of the b quark–antiquark pairs produced. large asymmetry could be expected between the decay rates of B0 in California and KEK in Japan, respectively. In 2001, the fi rst from experimentalists and theorists alike. indeed, because the As with BaBar and Belle, LHcb is equipped with excellent 0 and B mesons to the J/ψ KS fi nal state, as a function of time after results from the two experiments were enough to establish that cP properties of quarks can be studied only through fi nal states con- vertexing and particle-identifi cation capabilities. An additional production (carter and Sanda 1981, Bigi and Sanda 1981). is indeed violated in the B system (CERN Courier April 2001 p5). taining hadrons, detailed knowledge of the properties of the strong challenge for an experiment at a hadron collider is the effi cient To make the observation, however, would require much larger By the time that the research programmes at the B factories had interaction specifi c to each interaction is necessary to obtain quan- rejection of minimum-bias events that occur at a high rate. This is numbers of B mesons than had been produced in previous experi- been completed, the accelerators had broken records for the high- titative information about cP violation. in a few “golden modes”, achieved in LHcb by exploiting signatures of the decay products ments. Moreover, it would be necessary to have a precise measure- est instantaneous and integrated luminosities of any particle col- such as the measurement of sin(2β), the associated uncertainties of heavy fl avoured particles, such as muons with comparatively
ment of the decay time, together with knowledge of the fl avour of lider, allowing the measurement of the cP-violation parameter in are negligible. But for others such as εK, input from, for example, high transverse momentum and a secondary vertex that is signifi - 0 the B meson at production – that is, “fl avour tagging”. To meet B →J/ψ KS decays to be improved to a precision of better than 3%. lattice QcD calculations, is essential. cantly displaced from the proton–proton interaction point. unlike ▲ these challenges, several different designs were put forward, with This parameter is referred to as sin(2β), because it is sensitive to The large samples of B mesons available at BaBar and Belle the B factories, LHcb can study all types of b hadron – a feature
26 27 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Flavour physics Flavour physics
0 experiments. one good example is the decay mode Bs →J/ψ φ, which 1 0 0 CP-violation sensitivity Hyper-K Δ χ2=1 is the B sector equivalent of B →J/ψ K , and probes a parameter 700 KW, 100 kt.yrs 0.01 s S 12 β β ° +1100 KW, 200 kt.yrs 7.5 MW year labelled s. in the Standard Model, s is expected to be around 1 , +2300 KW, 200 kt.yrs whereas the latest results from LHcb and other experiments limit its
value to less than about 4°. Similarly, the parameters describing cP 2 8 0 0 0 0 0
0.00 violation in the B –B (and Bs –Bs ) mixing amplitudes, which are the δ ( π ) 5 1 B-system equivalents of εK, are expected to be vanishingly small. = Δχ 2 This has been a topic of considerable interest during the past few 4 3 3 ) 0
S years, because the D0 experiment based at Fermilab’s Tevatron
(B –0.01 reported an anomalous charge asymmetry in events with two same- SL A sign muons (CERN Courier July/August 2010 p6). These same-sign 0 –1 muons occur in events where both particles resulting from the –1.0 –0.5 0 0.5 1.0 0 0.05 0.10 0.15 δ /π sin22θ hadronization of a b quark–antiquark pair decay semileptonically, CP 13 –0.02 but one of them decays only after oscillating into its antipartner. The Fig. 4. CP-violation sensitivities of future long-baseline neutrino experiments. Left: Expected sensitivity to reject the hypothesis of
inclusive asymmetry could, therefore, be caused by cP violation in no CP violation, as a function of δCP, for different beam and detection capabilities of LBNF in the US (C Adams et al. 2014 0 0 0 0 2 either or both of the B –B and Bs –Bs mixing amplitudes. However, arXiv:1307.7335). Right: Expected contours on the δCP–sin 2θ13 plane for different true values in Hyper-K in Japan (Hyper-K –0.03 measurements of the parameters describing cP violation in each of Working Group 2013 arXiv:1309.0184). the two amplitudes individually do not reveal any discrepancy with –0.02 –0.01 0 0.01 the Standard Model, as fi gure 3 shows. Improved measurements are no hints of a nonzero electric dipole-moment. as possible. in this regard, it might be that the next big breakthrough 0 ASL (B ) needed to resolve the situation and are eagerly anticipated. Perhaps the best chance of a discovery of a new source of cP in the fi eld comes from the same particle that started the whole fi eld contemporary cP-violation searches are not confined to violation in the medium-term future is in the lepton sector. neu- off 50 years ago. Decays of kaons to fi nal states containing a pion Fig. 3. Constraints on the parameters describing CP violation in B mesons. Heavy-flavour experiments are abundant sources of trino oscillations can be described by the Pontecorvo-Maki-nak- and a neutrino–antineutrino pair can provide a theoretically clean 0 0 0 0 0 B –B and Bs –Bs mixing amplitudes, denoted ASL(B ) and charm hadrons, which can be used to investigate matter–antimatter agawa-Sakata mixing matrix in an analogous way to the cKM measurement of the height of the unitarity triangle, and therefore of 0 0 0 ASL(Bs ), from the D0 dimuon measurement (green ellipse) asymmetries. indeed, D –D oscillations provide a particularly matrix of the quark sector. (However, because the leptons do not the amount of cP violation described by the cKM matrix. Moreover, together with world averages of the individual parameters (blue interesting “laboratory” for such searches, because this is the only couple to the strong interaction, the phenomenology of quark and because these decays are highly suppressed, they are highly sen- bands) from measurements by BaBar, Belle, D0 and LHCb, and system involving up quarks in which phenomena similar to those lepton mixing is, in essentially all other respects, completely dif- sitive to physics beyond the Standard Model. Within the next few their combination (red fi lled ellipse). The Standard Model point measured in the K0–K0 and B0–B0 systems can be probed. Within ferent.) The recent measurement of a nonzero value of the mixing years, the nA62 experiment at cern and the KoTo experiment
is indistinguishable from the origin. (Image credit: Heavy the Standard Model, the cP-violating effects are tiny, which provides angle θ13 by Daya Bay (CERN Courier April 2012 p8) and other at J-PARC will improve signifi cantly on previous measurements of Flavour Averaging Group, www.slac.stanford.edu/xorg/hfag/.) a potential opportunity for new physics signatures to appear. The experiments shows that all three fl avours of neutrino mix with these decays, and might, therefore, start to provide hints of cP viola- small mixing rates make these measurements extremely challeng- each other to give the physical eigenstates, which is a prerequisite tion beyond the Standard Model. Such a discovery would provide that allowed it to make the fi rst observation of direct CP violation ing, but experiments have now been able to establish the mixing for cP violation to be observable. fertile ground for investigations for the next 50 years. 0 in Bs meson decays (CERN Courier June 2013 p7). LHcb has also phenomena at a high level of signifi cance (CERN Courier november The parameter that describes cP violation in neutrino mixing, ● discovered very large – and rather puzzling – cP-violation effects 2012 p7). consequently, charm-physics experiments are becoming δcP, can be measured by comparing the probabilities for electron Further reading in decays of B mesons to three particles (pions or kaons) (CERN more focused on cP violation, and further progress can be foreseen (anti)neutrino appearance in a muon (anti)neutrino beam. The J Baron et al. ACME collaboration 2014 Science 343 269. Courier november 2012 p7), which need to be understood with as the accumulated data samples increase. MinoS experiment, which detects neutrino beams from Fermilab A Carter and A Sanda 1981 Phys. Rev. D 23 1567. further experimental and theoretical investigations. Because the top quark does not hadronize, it must be studied in with a far detector at a baseline of 735 km in the Soudan mine in I Bigi and A Sanda 1981 Nucl. Phys.B 193 85. different ways from the lighter heavy quarks. it is also, of course, an Minnesota, and the T2K experiment, which uses neutrinos from M Kobayshi and T Maskawa 1973 Prog. Theor. Phys. 49 652. Future prospects excellent tool for probing beyond the Standard Model. Among the the Japan Proton Accelerator complex (J-PArc) and a far detector A Sakharov 1967 Pisma Zh. Eksp. Teor. Fiz. 5 32. What, then, remains for studies of cP violation? one important many tests of the top sector being performed with the unprecedented 295 km away in the Kamioka mine, have already made fi rst steps in point is that the measurements shown in fi gure 2 are, on the whole, samples collected by the ATLAS and cMS experiments are stud- this direction. now the novA experiment is also under way in the Résumé not limited by theoretical uncertainties. Because the consistency of ies of cP violation in both the production and decays of top quarks. uS, using the upgraded beam at Fermilab with a baseline of 810 km Violation de CP : les perspectives the measurements provides strong constraints on theories of phys- The discovery of a Higgs boson also provides the opportunity for (p30). However, far better sensitivity will be needed. For this reason, ics beyond the Standard Model, there is good motivation to con- ATLAS and cMS to search for cP violation in the Higgs sector, new and upgraded experiments have been proposed. These include Cinquante ans après la découverte de la violation de CP, l’intérêt tinue to improve them. For example, the measurement of the angle which is absent in the Standard Model. the Long Baseline neutrino Facility (p12) in the uS and Hyper- pour les différences entre le comportement de la matière et de γ achieved by studying cP-violation effects in B → DK decays has indeed, the description of cP violation within the context of the Kamkiokande (Hyper-K) in Japan, as well as possible projects in l’antimatière reste très vif. En 2001, les expériences ont montré
negligible theoretical uncertainty. The current constraint, combin- Standard Model is highly restrictive: it appears only among the europe and elsewhere. example sensitivities to δcP in these experi- pour la première fois qu'il existe une violation de CP dans les ing results from BaBar, Belle and LHcb, gives an uncertainty of flavour-changing interactions of the quarks. As a consequence, ments are shown in fi gure 4. Because the observation of CP viola- mésons B comme dans les kaons neutres. Depuis lors, un immense about ±10°. reducing this uncertainty by an order of magnitude tests of cP violation in other sectors can be carried out with zero tion in the lepton sector would give the possibility to explain the travail accompli aussi bien par les expérimentateurs que par les will either further constrain models that contain new sources of Standard Model background, and are therefore particularly sensi- baryon asymmetry of the universe, through a mechanism known as théoriciens a permis de conclure à une concordance remarquable cP violation or, perhaps, reveal the presence of new physics. This tive to new sources of asymmetry. in addition to the examples given leptogenesis, these projects are among the highest-priority science entre les données expérimentales et la théorie de Cabibbo- is one of the main objectives of the next generation of B-physics above, searches for nonzero electric dipole-moments of fundamen- goals in the international particle-physics community. The construc- Kobayashi-Maskawa prédisant le phénomène. Cependant, il existe experiments: the upgraded SuperKeKB accelerator and Belle2 tal particles such as the electron are sensitive to fl avour-conserving tion and operation of such projects might take 20 years, but if cP encore la possibilité de mesures améliorées qui permettraient de detector at KeK, and the LHcb upgrade at cern. cP-violation effects. owing to the amazingly high precision that violation is discovered in the lepton sector, it will be worth the wait. fi xer des limites à d’éventuelles nouvelles sources de violation de There are several other important cP-violating observables in the is achieved in experiments, the measurements are sensitive to the nonetheless, no one knows currently in which, if any, of these CP, ou, peut-être, de révéler une nouvelle physique. B system, where the Standard Model predicts small effects, but new small effects that are expected to be induced by new physics at the sectors the new sources of cP violation that must exist will appear physics could result in much larger values being measured in tera-electron-volt scale (Baron et al. 2014). As yet, however, there are fi rst. It is therefore essential to continue to explore on as many fronts Tim Gershon, University of Warwick.
28 29 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 Fermilab NOvA takes a new look at neutrino oscillations
A big detector and a powerful beamline will offer further insight into the masses and mixings of neutrinos.
NOvA, Fermilab’s new fl agship neutrino-oscillation experiment, has recorded its fi rst neutrinos and is now poised to make precision
measurements of electron-neutrino (νe) appearance and muon-neu- trino (νμ) disappearance. These data will help to unravel remaining unknowns in understanding neutrino masses and mixing. in the now standard picture of neutrinos, the three electroweak fl avour
states (νe, νμand ντ) are mixtures of the mass eigenstates (ν1, ν2 and ν3) related by a unitary matrix that is parameterized by three mixing
angles and a charge-parity (cP) violating phase. neutrinos are pro- 3D schematic of view from the top particle 1 duced and detected in fl avour eigenstates but propagate in mass NOvA particle detector eigenstates. interference among the mass states means that a neutrino interaction point
created in a defi nite fl avour state can later be detected in a different particle 2 neutrino fl avour state. This oscillation probability is determined by the sizes from particle 3 Fermilab of the mixing angles, the splittings in the neutrino masses, the energy PVC cell filled with liquid scintillator
of the neutrino and the distance it has travelled. Measurements of the view from the side particle 2 oscillation probabilities of neutrinos of known energy that travel a particle 1 known distance reveal the underlying mass-splittings and mixings. interaction point Thanks to experiments using neutrinos produced in the Sun, in neutrino from neutrino the atmosphere, at particle accelerators and in nuclear reactors, Fermilab from Fermilab researchers have found out a great deal about neutrino masses and 1 m particle 3 mixing. We know that two neutrinos are relatively close in mass and that the third is relatively far away in mass. We know that the mix- Fig. 2. Top: View of the NOvA far detector as the last module is ing angles are all relatively large, in contrast to mixing angles in the put into place. Bottom: Schematic of the NOvA detectors. (Image quark sector, which are small. We also know that the two neutrinos credits: Fermilab Visual Media Services.) that are relatively close in mass contain most of the electron-neutrino fl avour, and that the third is a nearly equal combination of muon and implications for cosmological measurements of the absolute scale tau fl avour. However, we do not know if the third mass eigenstate is of neutrino mass. The hierarchy, in combination with results from composed of more νμ or ντ, or if a new symmetry keeps these two neutrinoless double-beta decay experiments, plays an important contributions equal. We do not know if neutrinos violate cP sym- role in determining the Dirac or Majorana nature of the neutrino. metry, and we do not know the ordering of the neutrino masses. novA will use two detectors to measure oscillation probabilities neutrinos could follow a normal hierarchy, with most of the in Fermilab’s nuMi (neutrinos at the Main injector) muon-neutrino
νe content contained in the lightest two states, or they could fol- beam. When neutrinos travel the 810 km between Fermilab and
low an inverted hierarchy with the νe content predominantly in Ash river, Minnesota, through the crust of the earth, scattering of
the heaviest two states. The neutrino-mass hierarchy is one spe- νe on atomic electrons can either enhance or suppress the oscilla- ▲ cific prediction of different grand-unification theories, with tion probability, depending on the mass hierarchy. The effect is
Fig. 1. Photograph of the NOvA near detector, taken from a beam’s-eye view. (Image credit: Fermilab Visual Media Services.)
31 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Fermilab Fermilab
NOνA preliminary NOνA preliminary NOνA preliminary 1.1 800 –300 0.20 vertical cells neutrino near detector on surface 1.0 –400 candidates horizontal cells 600 0.15 –500 0.9
0.10 –200 400
efficiency 0.8 fraction of cells
vertical cells –300 s (near detector only) 0.05 μ 0.7 far detector contained horizontal cells 200 2200 2400 2600 2800 3000 3200 z (cm) events 0.6 50 10 NOvA - FNAL E929 events/2 hits hits 1 –500 0 500 0.0 0.2 0.4 0.6 0.8 1.0 run: 14828/38 0 0 event: 192569/NuMI distance from centre (cm) efficiency UTC Tue Apr 22, 2014 224 225 226 227 228 200 400 600 800 1000 0 100 200 300 400 500 21:41:51.422846016 t (μs) q (ADC) event time (μs) Fig. 3. Left: The effi ciency of detecting a minimum-ionizing particle crossing a cell, as a function of the distance from the centre of the cell. Right: A histogram of the detection effi ciency at the far end of the cell, made across all of the cells in the detector. Fig. 5. Left: The reconstructed event from fi gure 3. Right: Timing distribution of other candidate neutrino events found in the far detector.
opposite in neutrinos compared with antineutrinos, so by comparing blocks were constructed horizontally on an enormous table, which candidates found in the far detector. The neutrino candidates pile up the oscillation probability measured in neutrinos with that measured 500 later pivoted them into a vertical position and placed them in the at the arrival time measured in the novA prototype detector delayed with antineutrinos, novA can determine the mass hierarchy, resolve 0 experimental hall. by the neutrino fl ight time between the two sites, confi rming that the nature of ν3, and begin the study of cP violation in neutrinos. x (cm) in addition to containing the scintillator, the PVc structure seg- novA can identify neutrinos among the cosmic-ray backgrounds. To achieve these goals, novA requires an intense neutrino and –500 ments the detector into 4 cm × 6 cm × 15.6 m channels. Light pro- While relatively simple cuts can be used to separate beam neu- antineutrino source. nuMi had routinely delivered 320 kW of duced in these channels by the charged particles that traverse them trino events from cosmogenic events, further suppression of cosmic 500 beam power to the MinoS and MinervA experiments during bounces 10 times, on average, before it is captured in a wavelength- rays is required to achieve the oscillation physics goals. Multivariate operation of the Tevatron. However, with Tevatron operations now 0 shifting fi bre. To ensure that enough light is captured in the fi bre, event-selection algorithms tuned to recognize the differing topolo- y (cm) ν ν ended, the accelerator complex has been reconfi gured to provide –500 a special PVC formulation with enhanced refl ectivity had to be gies of μ and e charged-current and and neutral-current interactions twice the beam power to the nuMi beamline (CERN Courier developed. The large size of the detector and the large number suppress the cosmic-ray background rate by a further two orders of october 2013 p6). During a shutdown of a year and a half starting 0 1000 2000 3000 4000 5000 z (cm) of channels required more than 10,000 km of wavelength-shifting magnitude. Data collected when the beam is known to be off confi rm 102 2 NOvA - FNAL E929 10 hits in the spring of 2012, a major rF upgrade in the Main injector was run: 14828/38 hits 1 1 fi bre – enough to stretch from the supplier in Japan to the Ash River that the necessary level of rejection can be achieved: the cosmic-ray event: 192569/NuMI 2 3 accomplished, reducing its cycle time from 2.2 s to 1.67 s. Addi- UTC Tue Apr 22, 2014 210 214 218 222 226 230 234 10 10 10 Laboratory in a single unbroken thread. background in a one-year exposure is predicted to be one event in the 21:41:51.422846016 t (μs) q (ADC) tionally, the recycler ring, which was key to antiproton generation This large-scale assembly project is now fi nished. The last detec- νμ sample and 0.5 events in the νe sample, well below the expected for the Tevatron, was converted to a proton accumulator so that Fig. 4. An event display showing a charged-current νμ candidate tor block was put in place in February of this year and the last of the signal rates of 75 and 15 neutrinos in these samples. protons can be integrated and stored during the Main injector ramp in the far detector. Two cosmic rays are also seen in the detector 11 million litres of scintillator made for the experiment was deliv- The novA collaboration is now eagerly awaiting data from the from 8 GeV at injection to 120 GeV. during the 10 μs beam spill. This event was recorded at a time ered in April. While the task of outfi tting the detector with electron- near detector, which are needed to measure the beam composition At the same time, the nuMi beamline underwent a transformation when only the front half of the detector was instrumented. ics is continuing through the summer, the experiment recorded its and energy spectrum before oscillations have developed. The near- to accommodate the higher proton intensities required for novA. fi rst neutrino event in November last year, and has analysed millions detector data will set the background expectation in the far detector
The neutrino target and focusing horns were replaced and reposi- of the neutrino-interaction cross-section and the 810 km distance of cosmic-ray tracks. This analysis has verifi ed that the scintillator, for the νe appearance channel, and determine the unoscillated event
tioned. The new beam provides higher-energy neutrinos on-axis, but from the neutrino source. Being big, however, is not enough. The PVC, fi bre and electronics work together as designed to move the rate as a function of energy for the νμ disappearance channel. in at 14 mrad off the beam axis – where the novA detectors are located detector must also be highly segmented to prevent the numerous scintillation light from the far end of the detection channels to where May, one sixth of the full near detector was turned on for the fi rst – the neutrino energy spectrum is peaked narrowly at 2 GeV, the per- cosmic rays that cross the detector from interfering with neutrino it can be recorded. As fi gure 3 shows, the effi ciency for detecting a time, and neutrinos were seen in the fi rst spills. NOvA researchers fect energy for the long-baseline oscillations that novA will study. events from Fermilab. Furthermore, to separate electromagnetic minimum-ionizing particle crossing a cell at the furthest end from are looking forward to an exciting summer. Beam began circulating again in the Main injector in September showers from electron-neutrino events from similar showers from the read-out is above 90%, which is key to the tracking and particle- 2013 and work started on commissioning the new accelerator in the other sources, especially the decays of π0 mesons, heavy materials identifi cation performance of the detector. Résumé recycler ring. The recycler is now normally included in operations, of high atomic number (Z) such as steel – which are normally used NOvA pose un nouveau regard sur les oscillations de neutrino and work is underway to “slip stack” routinely in this new machine – a to build large structures – have not been employed. First events delicate manoeuvre where one bunch is injected then shifted to a dif- The NOvA detectors (fi gures 1 and 2, pp 30–31) are a unique solu- cosmic-ray interactions are an excellent source for detector cali- La nouvelle expérience sur les neutrinos NOvA, installation-phare
ferent orbit to make room for a second bunch in the same rF bucket. tion to the particular challenges of observing νe appearance using the bration, but they are also a potential background to the neutrino de Fermilab, a enregistré ses premiers neutrinos et se prépare once the two bunches are merged, they are accelerated together. nuMi neutrino beamline. The novA far detector is a 14,000 tonne selection. While the nuMi beam is delivered in regular bursts, 10 μs maintenant à des mesures de précision de l’apparition de neutrinos This work is expected to bring the nuMi intensity to 450 kW by the detector, using 9000 tonnes of liquid scintillator – the largest quan- in duration, the high cosmic rate on the surface means that about électroniques et de la disparition de neutrinos muoniques. Ces end of the year, and ongoing upgrades to the Booster ring that feeds tity of liquid scintillator ever produced for a physics experiment – to 1.5 cosmic interactions are expected in the detector during the spill. données contribueront à élucider les éléments qui demeurent this complex are expected to bring the intensity to 700 kW within record the tracks of charged particles. The scintillator is contained on the other hand, after oscillations, a nuMi neutrino interacts in inexpliqués pour mieux comprendre des masses et du mélange another year. Since coming back up from the shutdown, the complex in a 15.6 × 15.6 × 60 m3, 5000-tonne PVc structure constructed from the far detector once every 12,000 spills, or only about once every des neutrinos. NOvA utilisera deux détecteurs pour mesurer les has achieved a peak beam power of more than 300 kW and delivered modules assembled at a factory operated by collaborators at the four hours. containment and directional cuts suppress the cosmic probabilités d’oscillation dans le faisceau de neutrinos muoniques almost 2.5 × 1020 protons to novA and the other two neutrino experi- university of Minnesota. A crew of more than 700 undergraduate rate by about a factor of 105, with only minimal loss of neutrino NuMi de Fermilab : l’un à Fermilab et un autre à 810 km de là, à Ash ments sharing the beam, MinoS+ and MinervA. students directed by 10 full-time staff members ran the factory. events. Figure 4 shows a charged-current νμ interaction identifi ed River, dans le Minnesota. La collaboration attend avec impatience in addition to an intense beam, novA also requires a massive far These pieces were shipped to the Ash river Laboratory in north- in the novA far detector, along with two cosmic-ray muons zip- que ces deux détecteurs soient achevés. detector and a functionally identical near detector. Like all neutrino ern Minnesota, where another 45 full-time staff members built the ping through during the beam spill. Figure 5 shows the same event, detectors, the novA detector must be big to overcome the small size 28 free-standing blocks that make up the detector. The 190-tonne reconstructed, as well as a timing distribution of other neutrino Mark Messier, Indiana University, and Patricia Vahle, William & Mary.
32 33 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 A PASSION FOR PERFECTION Faces & Places
C OLLaBOratiON Turkey to become associate member state of CERN
on 12 May, cern and Turkey signed an agreement admitting Turkey to cern associate membership, subject to ratifi cation by the Grand national Assembly of Turkey – the Meclis. Turkey was granted observer status at cern in 1961, and Turkish physicists are today active in the ALice, ATLAS, cMS and LHcb experiments at the LHc. They are also involved with cAST, nA63 and oPerA, as well as with experiments at the iSoLDe facility. Turkey operates a Tier-2 centre of the Worldwide LHc computing Grid, and 110 Turkish scientists are registered users of cern’s facilities. Turkey’s associate membership will allow it to attend cern council meetings and open up industrial collaborations. Turkish scientists can also become cern staff Taner Yildiz, Turkish minister for energy and natural resources, left, and CERN’s members and participate in cern’s training director-general, Rolf Heuer, together with the signed agreement. (Image credit: and career-development programmes. CERN-PHOTO-201405-100-89.)
a PPOiNtMENts Harry Weerts, in charge of physical science All change at Argonne and engineering at Argonne. (Image credit: ANL.)
Harry Weerts has been named as the interim cern and on hadron-collider physics with associate laboratory director for physical the D0 experiment at Fermilab’s Tevatron, sciences and engineering at Argonne serving as spokesperson for the experiment national Laboratory. Director of Argonne’s for six years. Before coming to Argonne, high-energy-physics division, he now he spent 23 years on the physics faculty at oversees the laboratory’s interdisciplinary Michigan State university. research programmes in physics, chemistry, At the same time, the high-energy-physics material science and nanotechnology. He deputy director, rik Yoshida, has agreed Vacuum solutions takes over from Peter Littlewood, who has to serve as interim director for the division. become director of the laboratory. Yoshida has been a researcher at both the LHc Weerts’ recent research has focused on detector concepts for a linear collider. at cern and at DeSY, where he served as the from a single source linear-collider physics and developing Previously, he worked in neutrino physics at spokesperson of the ZeuS experiment. Roberto Battiston, new president of the ASI. Battiston to head (Image credit: Michele Famiglietti/ Pfeiffer Vacuum stands for innovative and custom vacuum solutions worldwide, SpacePart12.) technological perfection, competent advice and reliable service. We are the only Italian Space Agency supplier of vacuum technology that provides a complete product portfolio: recently, on the study of cosmic rays in space. in particular, he is deputy spokesperson for ■ Pumps for vacuum generation up to 10-13 hPa Stefania Giannini, minister of education, the Alpha Magnetic Spectrometer, installed ■ Vacuum measurement and analysis equipment university and research, has appointed on the international Space Station in May ■ Leak detectors and leak testing systems roberto Battiston as president of the italian 2011 (CERN Courier october 2013 p22). ■ System technology and contamination management solutions Space Agency (ASi). Battiston, who succeeds Aldo Sandulli, was ■ Chambers and components A graduate of the Scuola normale of identifi ed through a procedure carried out by Pisa, Battiston is professor of experimental a selection committee set up last February. Are you looking for a perfect vacuum solution? Please contact us: physics at the university of Trento, where he worked for more than 30 years, on behalf of From a total of 55 applications, the committee moved in 2012 to set up a new institute for inFn, within international collaborations selected fi ve candidates that were presented to Pfeiffer Vacuum GmbH · Headquarters/Germany astroparticle physics and technology. He has in experimental particle physics and, more the minister for her choice. T +49 6441 802-0 · F +49 6441 802-1202 · [email protected]
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14.02.12_PhysicsWorld_3_Prod_GB_213x282.indd 1 12.02.14 16:46 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Faces & Places Faces & Places
a W a r D s Markov Prize recognizes pioneers in Knighthoods for Kibble and Virdee theoretical astrophysics and cosmology Tom Kibble and Tejinder (Jim) Virdee, both of imperial college London – and both igor Tkachev, of the institute for nuclear astrophysics and cosmology. Tkachev well known for their roles in the prediction research (inr) of the russian Academy of has made signifi cant contributions to the and detection of a Higgs boson – have been Sciences (rAS), Moscow, and Alexander development of the theory of the early awarded the uK’s highest honour in the 2014 Dolgov, of the Alikhanov institute for universe, while Dolgov elaborated the Queen’s birthday honours. Theoretical and experimental Physics, kinetic theory of elementary particles, Kibble, who receives a knighthood for Moscow, and inFn, have been awarded the including neutrinos, in the expanding “services to physics”, is distinguished for 2014 Markov Prize. They received the award universe. The Markov Prize was established his ground-breaking research in theoretical at the 2014 Markov readings, held at the inr by inr rAS in commemoration of Moisey physics across nearly six decades. He is one on 14 May, for “pioneering works in the fi eld Markov, who made pioneering contributions Left to right: The 2014 Markov Prize of the theoretical physicists whose work in Jim Virdee, right, shows Tom Kibble the of theoretical astrophysics and cosmology”. to neutrino physics, as well as to physics at laureates, Igor Tkachev and Alexander RF Power? the early 1960s became a key piece of the results from CMS on the discovery of a The laureates are both well known in the boundary between particle physics and Dolgov, with the director of INR, Victor Standard Model, through giving mass to the Higgs boson, announced in July 2012. the fi elds of elementary particle physics, cosmology. Matveev. (Image credit: INR.) W and Z bosons via a symmetry-breaking (Image credit: M Sanch/Imperial College.) mechanism that would require a new particle, s Y M P O s i u M dubbed the Higgs boson. He has also made “services to science”, also recognizes his signifi cant contributions to the study of the work campaigning for and promoting better Berkeley honours Nygren’s ingenuity dynamics of symmetry breaking near phase science education in Africa and india. transitions with many applications, including in the same honours list, David Delpy, the formation of structure in the universe and chief executive of the engineering and David (Dave) nygren, of Lawrence high energy. That history was the subject vortices in helium-3. Physical Science research council Berkeley national Laboratory (LBnL), of a talk and a discussion by a panel of six Virdee spearheaded the concept and (ePSrc) until March this year, received the has a distinguished record of detector- veterans (“survivors”) of the diffi culties design of the compact Muon Solenoid honour of commander of the British empire instrumentation inventions and innovations, and successes of prototyping, building and (cMS) experiment, which together (cBe) “for service to engineering and which have transformed research in particle operating the TPc. with ATLAS found the fi rst evidence scientifi c research”. EPSRC is responsible and nuclear physics and in cosmology. To TPcs were essential elements in the for the existence of a Higgs boson in for funding the uK’s contributions to honour him for his ingenious designs, mark ALePH and DeLPHi experiments at 2012. Virdee oversaw the construction research in nuclear physics at cern, in his impending retirement and, incidentally, cern’s Large electron–Positron collider of cMS and was deputy spokesperson particular at the iSoLDe facility, the celebrate his 75th birthday, more than and are now used in ALice at the LHc, then spokesperson for the collaboration neutron time-of-fl ight facility and the 150 physicists from around the world ICARUS (fi lled with liquid argon rather until 2010. His knighthood, awarded for Antiproton Decelerator. gathered at LBnL on 2–3 May for The Art than gas) at cern and the Gran Sasso of experiment – A Symposium to celebrate national Laboratory, and STAr at the Forty Years of Advances 1974–2014. Brookhaven national Laboratory. These and Welcomes from the director of LBnL’s other gaseous-detector technologies were physics division, natalie roe, and laboratory the subjects of talks, including one on the director, Paul Alivisatos, were followed by history of the fi eld – which is still evolving Dave Nygren: “inspirational and wise speakers who were invited to “look at current brilliantly with ever-improving performance beyond his years”. (Image credit: Jerry and emerging topics at the interface between 45 years after having been introduced to Przybylski.) RF Solutions. physics and experimental techniques and particle physics – that concluded with “...to methods, for subjects related to Dave’s be continued”. extensive international neXT collaboration. research”. Between them, they covered a TPcs are central to a number of past, nygren’s early work on pixel detectors varied selection of topical subjects to show current and proposed approaches to settle two for the ill-fated Superconducting Super “ways in which physics is currently, or will of the most perplexing problems to have beset collider (SSc) led to the development be, enabled by new and creative innovations science for some years – the nature of dark of smart pixel arrays, as now used in the in instrumentation and methods”. To matter and of neutrinos. experiments that ATLAS detector’s precision-tracking system recognize his work on cP violation, nygren’s use TPc technology in searches for weakly at the LHc. Pixel history, current status early career was recalled by his mentor and interacting massive particles (WiMPs), and r&D were reported by a speaker who then colleague, Jack Steinberger. which are leading candidates for dark-matter noted that “Half-baked ideas have been In a ceremony held on 15 May, Tom Kibble, left, received the Albert Einstein Medal it was in 1974 that nygren invented the particles, and for neutrinoless double beta a constant of pixel-detector development 2014, awarded by the Albert Einstein Society, Bern, to honour extraordinary time projection chamber (TPc), a simple and decay – to determine if antineutrinos are and there is [a] shortage of them today.” achievements related to Einstein’s legacy. Kibble is honoured in recognition of many brilliantly conceived device to record 3D identical to, or different from, neutrinos – nygren pushed the idea that fully depleted contributions, including those relating to symmetric properties of the non-Abelian tracking data for charged particles in a large were the subjects of talks on experimental charge-coupled devices (ccDs) could be gauge theories that underlie the Standard Model of particle physics, to mechanisms of gas-fi lled volume equipped with parallel searches that have been or are now operating, developed from the silicon-detector r&D the symmetry-breaking and synthesis of new elementary particles and to spontaneous electric fi elds (in which ionization electrons as well as others planned for various global done for the SSc. The LBnL ccD is now symmetry-breaking in cosmology. He received the medal from Hans-Rudolf Ott, right, drift) and magnetic fi elds (in which charged sites. Two of those showcased the latest of the standard for astronomical cameras and president of the Albert Einstein Society. (Image credit: S Widmer.) reaction products move on helical paths). nygren’s conceptual art: a high-pressure spectrographs. That development story The fi rst TPC, built at Berkeley, was used in xenon-gas TPc for the neXT experiment, in was presented thoroughly, as were others + –
the PeP-4 experiment at SLAc to study e e Spain, and an approach to detection of WiMP that dealt with detector techniques for the ▲ ● For more about Kibble’s work, see Books received, p49. annihilation interactions at, what was then, directionality. nygren is a member of the now projected international Linear collider 28 Sanford Drive, Gorham, ME 04038 USA Phone:36 207-854-1700 Fax: 207-854-2287 37 E-Mail: [email protected] www.megaind.com
Third_Page_2013 Tuesday, March 12, 2013 15:46 page 1cerncourierMagentaYellowBlacCyank www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Faces & Places Faces & Places
in Japan or the uS and the AriAnnA Mediterranean in neSTor. one concluding San Francisco Bay east shore, with a glorious neutrino-astronomy observatory in remark – “Dave, it could not have been done view of the bay and its iconic sights. After High-energy Antarctica. Perhaps less familiar to without you!” – was a common theme. A dinner, Pier oddone, former deputy-director particle and nuclear physicists is nygren’s view from the uS Department of energy, of LBnL and former director of Fermilab, physics carries on application of silicon-strip detectors to X-ray the prime supporter of much of the research spoke of nygren and the times, followed by imaging, which has become a widely used celebrated at the symposium, was provided LBnL’s Bob cahn, who read messages from method for digital mammographic screening by Jim Siegrist, associate director, Offi ce of a few of the people who were unable to attend in Bosnia and in europe, Japan and Australia, and is being High Energy Physics, Offi ce of Science. He the symposium. adopted globally – the basis of two talks at ended with another common theme: “Dave is The symposium closed with a broad, Herzegovina the symposium. truly remarkable. i am at a loss for words. He detailed survey of perspectives for further Talks also reviewed nygren’s obsession is inspirational and wise beyond his years – experiment. despite the fl oods with better detector performance applied which is getting really diffi cult.” ● For recorded presentations, visit to neutrino astronomy in Antarctic Dinner was a chinese-style banquet at https://indico.physics.lbl.gov/indico/ ice by icecube, and in the water of the a restaurant just west of Berkeley on the conferenceDisplay.py?confid=128. The fi fth edition of the Sarajevo School Students and lecturers at SSHEMP 2014 express their appreciation that the school proved s C h O O L s of High energy and Medical Physics to be stronger than the fl oods. (Image credit: Ilja Doršner.) (SSHeMP 2014) took place at the university JUAS celebrates of Sarajevo on 19–24 May, against a This was a real challenge, considering the The support of cern, together with that backdrop of one of the biggest natural fact that the closures of roads, bridges and of icTP, PArSeco, uneSco through 20th anniversary disasters ever to have affected Bosnia and border crossings in Bosnia and Herzegovina Physique sans Frontières and the French Herzegovina and neighbouring countries. coincided with the start of the school, which embassy in Sarajevo, has been particularly The unprecedented fl oods and landslides attracted 60 students and lecturers from important in organizing the school and did not prevent advanced undergraduate and Albania, Belgium, Bosnia and Herzegovina, giving it its international status. The Joint universities Accelerator School graduate students interested in high-energy Bulgaria, croatia, egypt, France, ● For more about SSHeMP 2014, visit http:// (JuAS) celebrated its 20th anniversary at and medical physics from fi nding inventive Macedonia, norway, Poland, rumania, www.pmf.unsa.ba/fi zika/SCHOOL/HOME. the Laboratoire de Physique Subatomique ways to reach Sarajevo and attend the school. Serbia, Slovenia, Switzerland and Turkey. html. et de cosmologie (LPSc) in Grenoble on 25 April. The event brought together more than 100 scientists, lecturers, students and CAS covers power institutional partners to share a special day dedicated to the school, and provided an converters opportunity to look back on the past 20 years and to debate the future. The morning session was opened by Annick Billebaud, director of LPSc, with The cern Accelerator School (cAS) welcoming remarks and a brief history of and the Paul Scherrer institute (PSi) the laboratory where JuAS was conceived organized a specialized course on power in the early 1990s. She was followed by converters at the Hotel du Parc in Baden, Hans Hoffmann, president of the european Switzerland, on 7–14 May. Following some Scientifi c Institute (ESI), who presented the recapitulation lectures on accelerators and schools organized by the institute. the requirements on power converters, the Alex Mueller, research director at cnrS/ course covered a range of topics related in2P3, then discussed the challenges faced to the different types of power converters by today’s accelerators and the technology Top: Participants at the celebrations for the 20th anniversary of JUAS gather for the needed for particle accelerators. Topical Participants at the school in Baden. (Image credit: Markus Fischer/PSI.) paths currently explored for high energies and “family photo”. Above: Members of the round-table discussion. (Image credits: Chantal seminars completed the programme. high powers. in his talk, Steve Myers, former Argoud /ESRF-Grenoble.) The successful course was attended by Feedback from the participants was very a specialized school on plasma-wake director of accelerators and technology at 84 students representing 21 nationalities. positive, refl ecting the high standard of the acceleration to take place at cern on cern, reviewed particle accelerators in the contributed to the school’s success during that are raised by current particle While most of the participants were from lectures and teaching. in addition to the 23–29 november and a uS-cern-JAPAn- 20th century, as well as those foreseen for the the past 20 years. accelerators and future projects. The european countries, others were from Brazil, academic programme, the participants also ruSSiA Joint international Accelerator 21st century, with many applications other The afternoon session started with a pertinent interventions by students were an canada, china, iran, Jordan, Thailand had an opportunity to take part in a full-day School course on beam loss and accelerator than in high-energy physics. round-table discussion chaired by Frédérick encouraging sign that the new generation and the uS. Sponsoring in the form of visit to ABB, a major Swiss manufacturer of protection to be held in newport Beach, The coffee break provided an enjoyable Bordry, cern’s director of accelerators of accelerator scientists is well aware of the scholarships was offered by cAenels, power converters, and PSi and an excursion california, on 5–14 november. For more moment to meet past and present colleagues and technology. The participants included challenges that lie ahead. oceM and cern to students who would to the rhein Falls. information on both of these schools, visit and to exchange ideas. After the break, the morning’s speakers together with The day ended with a visit to the eSrF. otherwise have been unable to attend. ● Forthcoming cAS courses will be www.cern.ch/schools/cAS. Luigi Palumbo, director of the Department Philip Burrows, of oxford university and After a presentation of the synchrotron of Applied Sciences for engineering at spokesperson of the international compact radiation machine in the recently opened rome’s La Sapienza university, presented Linear collider (cLic) accelerator visitor centre, participants were able to the many facetted needs of accelerator collaboration, and Pantaleo raimondi, discover the control room, experimental training in the world. To conclude the director of the Accelerator Department beam lines and other equipment. To morning, Louis Rinolfi , director of JUAS, at the european Synchrotron radiation conclude, Bordry, Rinolfi and all of the ESI presented the past, present and future of Facility (eSrF). team expressed their sincere gratitude to Leader in VACUUM VALVES the school, paying tribute to former JuAS The ensuing lively debate confi rmed both all who took part in and contributed to this directors and all of the partners who have the real needs and the r&D opportunities important day for JuAS. www.vatvalve.com
38 39 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Faces & Places Faces & Places
v i s i t s C E r N 6 0 Greek president Karolos Synchrocyclotron Papoulias, seated, visited CERN on 3 May, where he was shown named EPS the ATLAS control room by ATLAS Greek team Historic Site leader, Evangelos Gazis, before visiting the ATLAS experimental cavern and CERN’s fi rst accelerator, the LHC tunnel. He also met with Synchrocyclotron (Sc), has been named a the Greek community at european Physical Society Historic Site. The CERN. (Image credit: CERN- honour came during the Sc’s inauguration as PHOTO-201405-095 – 28.) a new visitor point on 19 June, at a ceremony for cern council. When it started operation in 1957, the Sc was the highest-energy particle accelerator On 31 May, CERN took part in the parade celebrating Geneva’s 200th anniversary, with in europe, and during its 33 years of service a superconducting magnet from the LHC travelling through the city’s narrow streets on it provided many important physics results. a 20-m lorry. The event celebrated the bicentenary of Confederate troops landing at the Shut down in 1990, it has lain dormant since Port Noir, heralding Geneva’s integration into the Swiss Confederation. The parade (CERN Courier March 2014 p38). now, featured 1200 participants and took onlookers back in time to 1814 – complete with cern’s education and radiation Protection police offi cers and fi refi ghters in period uniforms and vehicles. With CERN’s presence, groups have jointly overseen an extensive the 21st century was not forgotten, and the organization used the occasion to showcase Phillip Paulwell, Jamaican minister of refurbishment project to turn the Sc into a its 60th anniversary. (Image credit: CERN-PHOTO-201406-113 – 35.) science, technology, energy and mining, signed new exhibition point for visitors. For more about the 60th-anniversary events, visit http://cern60.web.cern.ch/. the guestbook alongside CERN’s head of on the walls, timelines show important • international relations, Rudiger Voss, during moments in cern’s history, together with his visit on 14 May. He was shown the ATLAS associated tools and artefacts. But what experimental cavern and the LHC tunnel. (Image gives the accelerator a new lease of life is a N EW P r O D u C t s credit: CERN-PHOTO-201405-105 – 2.) 3D projection system. An intricate system of eight projectors displays six different Elsys Instruments has expanded its materials testing and research in images simultaneously onto the accelerator’s family of LAn-controlled transient high-energy physics and materials science. surfaces, projecting beautifully crafted recorders with a new series of The Model 2290-5 5kV Power Supply and On 15 May, Pavel Beˇlobrádek, animations. Visitors see protons fl it across high-resolution Pcie data-acquisition Model 2290-10 10kV Power Supply are Czech Republic deputy prime the room and magnetic fi elds expand in cards. The new data-acquisition suited for high-voltage breakdown testing minister for science, research clouds of blue haze, as a narrator explains a waveform-digitizing products deliver of power semiconductor components. and innovation and chairman of European commissioner for research, innovation and typical Sc run. each part of the process is prime performance in applications Keithley has also announced the new the Research, Development and science, Máire Geoghegan-Quinn, centre, came to CERN punctuated with a 3D display, giving a clear where the acquisition of high-speed, Series 2260B Programmable Dc Innovation Council, visited the on 19 May. She was shown the CMS experimental cavern picture of how the accelerator worked. high-resolution and high-precision Power Supplies, designed for benchtop, LHC tunnel, and ATLAS and ALICE by collaboration spokesperson Tiziano Camporesi, left, waveform data is of importance. embedded and manufacturing test experimental caverns. (Image credit: accompanied by CERN’s director-general. (Image credit: For additional information, tel applications that demand higher power CERN-PHOTO-201405-104 – 13.) CERN-PHOTO-201405-103 – 42.) +41 56 496 0155, e-mail thomas.berger@ and performance. The series includes two elsys.ch or visit www.elsys-instruments. 360 W and two 720 W models, offering a com/products/tpce-le.php. range of output levels, combined with LAn and uSB connectivity and an optional Goodfellow now offers silicon-carbide GPiB interface. For further information, On 21 May, His Majesty foam, which provides the hardness, visit www.keithley.com. Philippe, King of the high-temperature durability and Belgians, left, was performance of solid silicon carbide, but in The Kurt J Lesker Company has recently shown the LHC tunnel a lightweight and versatile foam structure. launched a new Feedthrough Selection by Frédérick Bordry, The foam is available from stock with Guide on its website. The selection director of accelerators 24 pores/cm, a bulk density of 0.29 g/cm3, guide helps users to select the proper and technology, centre, porosity of 91% and thickness of 10 mm. feedthrough for their application, based pointing, accompanied by Vytenis Andriukaitis, Lithuanian minister other porosities, densities and dimensions on their specifi c requirements. This visual Nobel laureate François of health, left, was welcomed by CERN’s may be available upon request. For more guide makes selecting the correct power, Englert, right. (Image director-general on 20 May, before being shown information, tel +44 1480 424 800, e-mail instrumentation, thermocouple, liquid, credit: CERN-PHOTO- the CMS experimental cavern. (Image credit: [email protected] or alternatively visit gas, liquid nitrogen, ceramic break, or 201405-109 – 23.) CERN-PHOTO-201405-107 – 4.) The Synchrocyclotron bathes in a blue neon www.goodfellow.com. fi bre-optic feedthrough quick and easy. For glow. The large spanners on the wall to the additional information on this new guide, right were used in the 1950s to tighten the Keithley Instruments, Inc., has tel +1 412 387 9200, e-mail salesus@
bolts on the accelerator’s red magnet (Image introduced two high-voltage power lesker.com or alternatively visit www. ▲ credit: Jacques Herve Fichet/CERN.) supplies optimized for device and lesker.com.
40 41 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 CERN Courier July/August 2014 Faces & Places Recruitment O B i t u a r Y F o r advertising e n q u i r i e s , c o n ta c t CERN C o u R i E R recruitment / c l a s s i F i e d, ioP P u b l i s h i n g , te m P l e c i r c u s , te m P l e Way, b r i s t o l bs1 6hg, uK. te l +44 (0)117 930 1264 Fa x +44 (0)117 930 1178 e- m a i l s a l e s @ cerncourier . c o m Robert Vinh Mau 1931–2014 P l e a s e c o n ta c t u s F o r inFormation a b o u t r at e s , c o l o u r o P t i o n s , Publication d at e s a n d d e a d l i n e s .
robert Vinh Mau, professor emeritus an extraordinary success, fi tting an immense at the université Pierre et Marie curie, amount of data. (in 1981, Mau sent Jean-Marc university of copenhagen Paris-Jussieu, passed away on 25 April at the richard to work with me at cern, with age of 82. whom i still have a wonderful collaboration.) Mau – his fi rst name in Vietnamese For this work on the potential, Mau – was born in Hué, a member of the received the Petit d’ormoy prize of the Vietnamese imperial family. He studied French Académie des sciences in 1983 and for his baccalauréat in Saigon and then the Alexander Von Humbolt prize in 1986. moved to France – fi rst to Grenoble for He also made other contributions with his undergraduate studies, where he was possible cosmological consequences (see, for handicapped by tuberculosis, and then to example, his article with nicolas Borghini in Paris. He obtained his PhD under roger La Recherche, no. 337 p52). nataf in orsay, on coulomb effects in inner Robert Vinh Mau and André Martin in Mau was a friend of eminent scientists, bremsstrahlung. discussion at CERN in 1960. (Image credit: such as nobel laureates Julian Schwinger in 1960, nataf sent him to work with me CERN.) and Leon cooper. He also liked to travel, at cern, where we worked together on for instance to Stony Brook and Berkeley, the analyticity of amplitudes in potential a nucleon–nucleon potential. Since Hideki but went once only back to Vietnam, to a scattering, and quickly became friends for Yukawa postulated what turned out to be conference in Hanoi. There he spoke in life. Mau then went to rome and Bordeaux, the pion, there had been many attempts to english to be understood by everyone, while where with B Bonnier in 1967 he found derive this potential. Working with noel the russians spoke only in russian. He also a fundamental lower bound on the pion– cottingham, who he had met at cern visited Saigon and found his house in ruins. pion scattering length. (This was later in 1960, Mau followed the proposal His last years were painful, not only for considerably improved by irinel caprini made by John charap and Sergio Fubini. himself but also for his wife, Mylène, who Associate Professorship in Experimental Particle Physics and Petra Dita.) Finally, Mau became They obtained, with the help of excellent showed admirable devotion. We will miss The Niels Bohr Institute Faculty of Science University of Copenhagen professor at the university in Paris-Jussieu, collaborators Jean côté, Benoît Loiseau, him a great deal. where he had important functions, as well as Michel Lacombe, Pierre Pirès, Jean-Marc ● André Martin, CERN, with The Niels Bohr Institute invites applica- ent research profile, and also to take a Managerial and out-reach qualifications at cnrS. richard and roland de Tourreil, what is called acknowledgement to Benoît Loiseau for tions for a position as Associate Professor prominent role in the teaching of gradu- of applicants including ability to attract Mau’s major contribution was to obtain the “Paris potential”, which was and remains allowing use of his speech at the funeral. in Experimental Particle Physics. ate and undergraduate physics students. external funding will also be considered.
N EW P r O D u C t s C O N t i N u E D The position is open from 1 January 2015 Applicants are required to have university Further information on the Department The Proton Synchrotron Booster or as soon as possible thereafter. The level teaching experience, documented is linked at www.science.ku.dk/english/ Murata has announced the MTu2 series of (PSB) is one of the smaller Niels Bohr Institute at the University of teaching competencies and must be able about-the-faculty/departments/. Inquir- ultra-miniature surface-mounted 2 W Dc– machines in CERN’s accelerator Copenhagen is expanding its activities to explain and reflect upon own teaching ies about the position can be made to Dc converters from Murata Power Solutions, complex. The concept behind it in particle physics, astroparticle physics practice and portfolio. Formal pedagog- Head of Institute, Robert Feidenhans’l at measuring 8.2 × 8.4 × 8.5 mm2 with a 0.69 cm2 dates back to the mid-1960s, when and cosmology. The Institute hosts the ical training or supervision equivalent to [email protected] or Deputy Head of In- footprint. With a typical conversion effi ciency ideas to improve the performance of the PS by Discovery Center for Particle Physics and the University of Copenhagen teacher stitute for Research Niels Obers at of 85% across the full load range and a raising its output beam intensity from 1012 to 1013 Cosmology which is funded by the Dan- training programme for assistant profes- [email protected]. power density of 3.403 W/cm3, the MTu2 protons per pulse were being considered. One of ish National Research Foundation. The sors is required. series is available with either a single- or a kind, it consists of four superimposed center has a vigorous research program Please find the full job advertisement dual-output voltage. For more information, synchrotron rings, into which the beam from the that spans all areas of theoretical and ex- Duties include the applicant’s own re- http://employment.ku.dk/ . contact Aya Tonooka, tel +44 1252 811666, linac is successively injected. The four beams are perimental subatomic physics. search, development of the field, as- e-mail [email protected] or visit www. then accelerated and eventually recombined sessment tasks, grant applications, and murata.eu. after extraction before entering the PS. The top In particular, the program includes strong research management such as supervi- Only electronic applications are accepted. view was taken in October 1972, around the time participation in the ATLAS and ALICE ex- sion and training of research fellows and VadaTech has announced an 8u-high chassis the PSB began to feed the PS, just fi ve months periments at the LHC, both in the opera- other staff. The successful applicant must after accelerating its fi rst protons. The compliant with the MicroTCA.4 specifi cation tion and data analysis as well as in future also teach, supervise, prepare and par- that offers n+1 redundant power to 4400 W. photograph is taken at the position where beams upgrades. We seek an experimentalist ticipate in examinations, and fulfill other MicroTcA.4 systems utilize double modules emerge from the four levels of the booster on the with an outstanding research record in tasks requested by the Department. Founded in 1479, the University of Copenhagen with an rTM connector for rear i/o. With left and are brought progressively to the level of is the oldest university in Denmark. With 37,000 accelerator based experimental particle or specially designed power modules, the VT813 the PS. Since then, the PSB has undergone students and 9,000 employees, it is among the chassis has four 1100 W power supplies in several upgrades and in the LHC era (below right) it is operating with its highest heavy-ion physics, who will also be able Assessment of applicants will primarily largest universities in Scandinavia and one of the an N+1 redundant power confi guration. By availability and fl exibility, and far beyond its original design specifi cations. The aim is to further strengthen the ties between consider their level of documented, orig- highest ranking in Europe. The University consists of six faculties, which cover Health and Medi- aligning the compact power supplies on the to operate the PSB throughout the lifetime of the LHC, and ensure that it remains one of our theoretical and experimental activi- inal scientific production at an interna- ties. We expect the chosen candidate to tional level, including contributions to cal Sciences, Humanities, Law, Science, Social side of the card cage, the chassis can provide CERN’s backbone accelerators for the foreseeable future (cern courier September Sciences and Theology. 12 double-module, mid-sized slots. For more 2012 p33). (Image credits: CERN-AC-7210021 and CERN-PHOTO-201405-098-51.) contribute to our commitments to ATLAS developments in their field, as well as details, visit www.VadaTech.com. or ALICE, to have an ambitious independ- their documented teaching qualifications. www.ku.dk/english
42 43
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INSTITUT DE FÍSICA D’ALTES ENERGIES Consorci de la Generalitat de Catalunya i de la Universitat Autònoma de Barcelona The Universities of Liverpool, Lancaster and Manchester The Cockcroft Institute CALL FOR APPLICATIONS: DIRECTOR OF IFAE Director The Institute of High Energy Physics (IFAE), www.ifae.es/eng is a consortium of the Universitat Autònoma de Barcelona and the Salary Negotiable Generalitat of Catalonia. IFAE is part of the Catalan public network of The Cockcroft Institute (http://www.cockcroft.ac.uk/) is a unique research Institutes, CERCA (www.cerca.cat). international centre specifically responsible for research and development in particle accelerators, colliders and light sources for IFAE conducts experimental and theoretical research at the frontier advancing the frontier of particle and nuclear physics, photon sciences of fundamental physics, namely in Particle Physics, Astrophysics and and various applications to society in the areas of health, medicine, Cosmology. IFAE also works at the cutting edge of detector technology, energy and security. The Institute is a partnership between the applying its know-how to Medical Imaging and other applied research Universities of Liverpool, Manchester and Lancaster and the Science fields. It maintains a fruitful collaboration with its spinoff company, and Technology Facilities Council. X-Ray Imatek. We are seeking to appoint a Director of the Institute who will grow its In 2012, IFAE was granted the Severo Ochoa award, given by the reputation as a world-leading centre for accelerator science. Reporting Spanish government to a few leading national research centres. to the Institute Board, the Director will work with the partners to develop strategy for the Institute and manage all aspects of its implementation. You will have a successful track record in accelerator Candidate profile and contact information science or a related field and have demonstrated ability in leadership in IFAE is seeking applicants with a distinguished record of scientific a university or research organisation. The role of Director will be for 5 excellence and the innovative thinking necessary to lead a dynamic years initially, and will be offered in combination with a permanent organisation. A PhD or comparable degree, high international visibility professorial appointment in one of the partner universities. in IFAE’s field(s) of activity and significant research management The post is available from 1 January 2015 or as soon as possible experience are required. Salary will be commensurate with thereafter. qualifications and consistent with IFAE management’s salary scale. Job Ref: A-565563/CC Closing Date: 1 September 2014 More information, including a description of the Director’s post and responsibilities, is at www.ifae.es/eng/work/open-positions.html. For full details, or to request an application pack, visit The successful candidate may be offered an indefinite position as Full www.liv.ac.uk/working/job_vacancies/ or e-mail [email protected] Research Professor. The appointment as Director will be for a period Please quote job ref in all enquiries. of 4 years, which could be extended. Applicants should send a CV and a cover letter by e-mail to the Director of CERCA, at applications@ COMMITTED TO DIVERSITY AND cerca.cat, citing as the subject “IFAE Director call”. EQUALITY OF OPPORTUNITY
The deadline for applications is October 10, 2014.
Four Faculty Positions In Theoretical Physics and Mathematics Departments of Mathematics and Physics University of California, Davis
The Departments of Mathematics and Physics at the University of California, Davis invite applications for four full-time faculty positions to launch a new research initiative: The Physics and Mathematics of the Universe. Applications will be considered for appointment at the level of Assistant Professor, Associate Professor or Professor; appointments will be made either in the Mathematics or Physics Department, or jointly between the two departments, to be determined on a case-by-case basis. This is an opportunity to build an extraordinary program, and we will exercise flexibility regarding the exact specialties of the faculty we recruit in order to achieve an exciting outcome. We encourage applications from candidates with expertise in areas of theoretical physics and mathematics that aim to increase our understanding of the fundamental physical laws and their underlying mathematical structure. This program will benefit from synergies with our strong research programs in high energy physics, gravity, cosmology, geometry, topology and mathematical physics. Applicants must have a Ph.D. in physics or mathematics and the ability to teach effectively at both undergraduate and graduate levels. Demonstrated success in an active research program in physics or mathematics is essential. Due to the large number of positions to be filled, applications will be evaluated starting October 10, 2014. To ensure full consideration, applications should be received by this date. The positions will remain open and applications will be accepted until the search is complete. Applications should be submitted online via the job listing PMUFAC2014 on http://www.mathjobs.org, and should include a cover letter, CV, publication list, research and teaching statements, and letters of recommendation from at least four references. Inquiries may be addressed to PMU Search Committee Chair, Department of Physics, University of California, One Shields Ave, Davis, CA 95616, or by e-mail to [email protected]. Further information about the departments may be found on our websites at http://www.physics.ucdavis.edu and https://www.math.ucdavis.edu.
UC Davis is an affirmative action/equal employment opportunity employer and is dedicated to recruiting a diverse faculty community. We welcome all qualified applicants to apply, including women, minorities, individuals with disabilities, and veterans.
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Summer Bookshelf With summer well under way in the northern hemisphere, this Bookshelf features less technical books, and includes cartoons and even a fi lm review – all on particle physics or EXTRAORDINARY closely related themes. Currently we are looking for: Un diplomate dans le siècle ; souvenirs et // Technical safety coordinator anecdotes By François de Rose // Senior designer-Experimental Programmes Editions Fallois // Expert for cryogenic systems Paperback: €10 Also available at the CERN bookshop // Technical requirement specialist François de rose est un grand témoin JOB e du XX siècle. né en 1910, il a vécu les OPPORTUNITIES // Laser and Optical specialist deux guerres qui déchirèrent l’europe, la Unique opportunity to be involved in defining and reconstruction de la paix, et tous les grands implementing the state-of-the-art laser technology and // PhD position construction of a new EU science facility. événements du monde d’hier. Diplomate, il a évolué dans les cercles des puissants et de leurs conseillers, et s’y fi t des amis. Un jour de 1946, il fi t la connaissance de Robert oppenheimer et se lia d’amitié avec le www.eli-beams.eu/cooperation/jobs/ célèbre physicien. Dès lors, il mit ses talents Le recueil fait une belle place au cern, are little gems, but they are jumbled up, de diplomate au service des scientifi ques « la plus belle plume à mon bicorne disordered and congested. The book reads qui voulaient reconstruire la science d’ambassadeur », dit-il. François de rose like a series of digressions and there are fondamentale en europe. il devint ainsi raconte ses rencontres avec niels Bohr, enough typos and mistakes – bacteria and l’un des fondateurs du cern. il poursuivit Pierre Auger ou robert oppenheimer, de criteria are plural not singular, the shadow ensuite Visitsa carrière diplomatique, comme grands noms de la physique aujourd’hui on a sundial is not cast by a gnome – to ambassadeur et spécialiste des questions entrés dans la littérature. il relate comment irritate anyone trying to stay the course. FACULTY POSITION IN EXPERIMENTAL CONDENSED stratégiquesfor your et militaires. next career moveil embrassa la cause du CERN et sa fi erté concepts seemingly pop up out of MATTER François de rose n’écrivit jamais ses d’avoir vu ce projet couronné de succès. nowhere, reappearing again (and again and UNIVERSIDAD DE LOS ANDES – BOGOTA, COLOMBIA mémoires, bien que ses amis l’aient pressé de Écrit avec élégance, ce recueil s’apprécie again) when the plot is all but lost. Much le faire. Mais à l’orée de ses 103 ans, il s’attela comme une boîte de friandises, exquises et of the material is erudite, abstruse and The Physics Department at Universidad de los Andes, Colombia, is à la rédaction d’un recueil de souvenirs. ce légères, aux saveurs d’antan. irrelevant, such as “The delta particles Δ–– Δ– seeking to fill a position in experimental condensed matter physics petit livre, intitulé Un diplomate dans le ● Corinne Pralavorio, CERN. Δ0 Δ+ are like neutrons and protons but with for a faculty member at the level of assistant or associate professor. siècle, parut le 13 mars 2014. Dix jours plus complex spin.” Spin, complex or not, is not Applicants are expected to have expertise in one or more of the tard, son auteur s’éteignait à Paris. Le cern How Big is Big and How Small is Small: in the too-brief index, so the reader cannot following areas: nano-magnetism, transport measurements (high perdait son dernier fondateur. The TheSizes ofjobs Everything site and Why check whether it has been defi ned earlier, or magnetic fields and low temperatures) and functional layered François de rose était un homme plein By Timothy Paul Smith indeed anywhere, and the doubly charged materials (fabrication, growth and characterization). d’esprit, et un esprit libre. Son élégance et Oxfordfor Universityphysics Press and member of this quartet is actually the Δ++, sa liberté de pensée scintillent au travers de Hardback: £25 although by now – page 123 – it is debatable This position should complement and extend our existing engineering ces anecdotes relatées au gré « des caprices Also available as an e-book, and at the CERN whether even the most interested readers experimental strength in condensed matter physics. qui (lui) restent de mémoire ». François bookshop care. And why should they? For more information, refer to: de rose raconte « un temps que les moins This book canters through the sizes and Some aggressive editing would have been http://fisica.uniandes.edu.co/index.php/en/research/ de cent ans ne peuvent pas connaître », il lifetimes of things, from the outermost in order, not only to fi x imperfections and condensed-matter égrène avec humour des histoires qui ont reaches of the universe to the confi ned remove chunks of repeated or unnecessary A Ph.D. degree, postdoctoral experience and commitment to marqué sa vie. Du baisemain à l’impératrice locality of quarks, telling us what is found text, but also to avoid slowing down the excellence in independent research and teaching are required. eugénie en 1920 à la fête d’anniversaire where and why, and is, according to the observant with infelicitous phrasing, for Applicants should send a curriculum vitae, a description of research d’Henry Kissinger en 2013, il est tout à fait publisher’s website, suitable for “interested example, “A number of species in the and teaching interests, and arrange to have three recommendation fascinant de parcourir cette existence longue general readers as well as professional new world and the old world have the letters sent to: et riche, celle de l’un de nos contemporains scientists” – a broad church. same common name because, at least Carlos Avila, qui fut aussi le contemporain de George Vi in scanning 45 orders of magnitude, the superfi cially, they look the same, for Chairman, Physics Department, Universidad de los Andes et d’Albert einstein. cet humaniste livre une author presents a wealth of information on example the robin and the buffalo.” e‐mail: director‐[email protected] e A.A. 4976, Bogotá, Colombia. foule d’anecdotes sur la diplomatie au XX “everything”, from cosmology to string And in a cup of water drawn from an Phone (57‐1)‐332‐4500, Fax (57‐1)‐332‐4516. siècle, les hasards heureux ou malheureux, theory, with passing reference to cooking, ocean today, how many molecules were in les grandes phrases et les petites histoires qui football, square dancing and more. The a cupful poured into the oceans long ago? The jobs site for physics construisentThe l’histoire jobs avec site un grand « H ». narrative is exuberant and many of the facts After 10 pages of exhaustive and exhausting Review date: July 31st 2014 More than Desired starting date: January 2015, however the position will for physics and remain open until a suitable candidate is found. and engineering engineering 23 000 47 The jobs site for monthly unique CCJul14Classified43,44,46.indd 46 physics and 02/07/2014 13:00 visitors engineering cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4
M Bright AD 0111 Odd Size fillers.indd 3 02/07/2014 12:47 CERN Courier July/August 2014 CERN Courier July/August 2014 Bookshelf Bookshelf
accounts of the work of Avogadro, Dalton, physics for many years. presentations given at a symposium held Gay-Lussac, Loschmidt and Maxwell, we As advertised in the subtitle, the cartoons in March 2013 at the Blackett Laboratory, arrive at the numbers. There are 3.3 × 1024 cover a variety of topics in physics, but imperial college London, to celebrate his water molecules in a cup and 1.3 × 1022 cups in mainly focus on phenomena at the largest 80th birthday. The symposium profi led the oceans. So, 250 of the original molecules and smallest scales. Some are decidedly various aspects of his long scientifi c career, are in today’s cup and, although not stated, whimsical, while others are more didactic, with talks from neil Turok, Wojciech Zurek the oceans contain 4.3 × 1046 water molecules. and some seem to hark back to an earlier and Jim Virdee, and in the evening, Steven Yes? no! on the following page, “there are age in terms of the representation of women. Weinberg and Frank close. about 8 × 1045 molecules of water on earth.” This said, there is enough variety to bring i was once told, if lost for affable words a smile to most physicists, and at least now Microcosmos: The World of Elementary when asked for an opinion on something when people use one of Grupen’s cartoons, Particles. Fictional Discussions between quite extraordinary, to say “astounding!” they might know whom to credit. Einstein, Newton, and Gell-Mann This book is astounding, which is a pity as it ● Christine Sutton, CERN. By Harald Fritzsch could and should have been excellent. World Scientifi c ● Peggie Rimmer, Satigny/Oxford. power and his competition with the young Hardback: £18 and most-important scientist of the epoch – Film review Also available at the CERN bookshop Henri Poincaré: A Biography Through the not addressed, i wonder what priorities led Particle Fever Suitable for non-experts in Daily Papers to selection of the material that is presented. “He was ALWAYS there!” This was the physics, this book provides a By Jean-Marc Ginoux and Christian Gerini There is the “Dreyfus affair”, which is reaction of cern scientists who spent broad introduction to the fi eld World Scientifi c discussed amply and where Poincaré played years being followed by fi lm-maker Mark of particle physics through Hardback: £19 an honourable role. This was clearly of Levinson. The result is Particle Fever – a fi ctional discussions between E-book: £14 contemporary importance, but historically, feature-length documentary about cern, three prominent physicists — Henri Poincaré: A Biography Through looking at Poincaré the pre-eminent which has been touring cinemas and Albert einstein, isaac newton, and Murray the Daily Papers – where papers clearly mathematician, this is a footnote at best. festivals, reaching audiences far beyond Gell-Mann — together with a modern include letters, because many are included on the other hand, the presentation of his particle physics. Why? Because Levinson physicist. Matter is composed of quarks and – has caused some confusion in my mind. involvement in ernst Mach’s thinking and manages to capture, through his narrative and electrons. By following these discussions, Turning the pages, it is hard to know A search on the web reveals a the earth’s rotation is the high point of character-driven piece, a compelling story nonetheless, Monica delivers a spectacular the reader should acquire an overview of the where i am in time, and the events that recommendation letter from Poincaré this small book, and might yet justify its of passion, disaster, loss and then triumph. performance and was by far my favourite current status of particle physics and come are described seem to be of sub-relevance regarding the appointment of einstein at presence in the history of science literature. it is not “boy meets girl”, but scientists build “character”, with her candid pieces to to understand why particle physics is an to what i was keen to read about. Two eTH-Zurich written in november 1911 – see ● Johann Rafelski, University of Arizona. accelerator, scientists lose accelerator (in camera and analogies: “The entire control exciting fi eld. towering examples concern Poincaré’s www.lettersofnote.com/2013/11/one-of- the September 2008 incident), scientists get room is like a group of six-year-olds whose relation to politics and relativity. most-original-thinkers-i-have.html. in this Cosmic Cartoon Collection: Cartoons on accelerator running again and fi nd elusive birthday is next week…and there’ll be cake.” Physics and Our World i note that despite extensive discussion of letter, Poincaré the mathematician, who died Astronomy, Cosmology, Quarks, and other particle – cue thunderous applause. There is something incredibly Reissue of the Proceedings of a Symposium his interaction with the daily press, there is in 1912, characterizes einstein the young Physical Matters The fi lm focuses on a handful of CERN heart-warming about watching your place in Honor of Victor F Weisskopf only the briefest mention that Henri Poincaré physicist, who became noticed around By Claus Grupen characters, from the ATLAS experiment of work portrayed dramatically on the big By Kerson Huang (ed.) had an infl uential cousin, Raymond Poincaré, 1907–1912, as an oddity among scientists, Universitätsverlag Siegen mainly: Fabiola Gianotti, Martin Aleksa screen. Goosebumps came in waves with World Scientifi c who was president of France during the deserving a mention for this reason: “Mr Paperback: €5 and Monica Dunford, together with Mike the fi lm’s twists and turns, and I came away Hardback: £45 years 1913–1920 (and so covered the First einstein is one of the most original thinkers cartoons about science often take on a life of Lamont from the accelerator side. While thinking “Wow, i work there.” As a result, E-book: £34 World War), and before that a member of the i have ever met,” and going on to say, “Since their own, as people copy them to add interest this skews the fi lm away from the reality i pity my poor family, who will all have to As the proceedings of a French parliament, and on several occasions he seeks in all directions one must…expect to their presentations, hand them on, add them of thousands of collaborating physicists, it watch this at christmas, whether they want symposium that took place minister or prime minister. i had been hoping most of the trails which he pursues to be to their websites, blogs and so on. i once found enables a picture to form through the eyes to or not! in 1974 in honour of Victor to learn how close Henri was to raymond blind alleys.” This shows that Poincaré died an excellent one about neutrinos left on a of these protagonists of passionate people ● Kate Kahle, CERN. Weisskopf — the well-known and how this impacted on the opinion of the in ignorance of the fact that einstein had photocopier, which later became a key part of working together towards a common goal. ● Particle Fever is currently touring cinemas theoretician, who was cern’s French public on both of them – a genius already created several new paradigms of some of my talks. What often happens is that Levinson weaves in uS-based theorists and festivals, and is available to buy as an HD fi fth director-general during the mathematician and a powerful politician science, of which (special) relativity was the name of the cartoonist becomes lost as the David Kaplan, nima Arkani-Hamed and download worldwide from 15 July. For more years 1961–1966 — this volume contains from the same family. directly related to Poincaré’s own work. i cartoons become widely spread – especially Savas Dimopoulos to stitch together a details, see http://particlefever.com/. papers by leaders of physics at the time, i also hoped for a discussion of the wonder if there is any other evidence in the if the signature is small and becomes blurred dramatic narrative of a mighty quest for including Max Delbrück, Murray Gell-Mann, relation of Henri Poincaré to Hendrik press or in letters about what Poincaré knew with multiple copying. That seems to be the the Higgs boson. in being swept along Books received Hans Bethe, Tsung-Dao Lee, Ben Antoon Lorentz and Albert einstein. and thought about einstein? case with some of claus Grupen’s work. by the action, the audience is also taught roy Mottelson, Wolfgang K H Panofsky, There is only one phrase, on page 212 at the Having seen this letter, i believe that indeed, i was recently asked to identify the a fair amount of physics with the help of Symmetry and Fundamental Physics: edward Purcell, Julian Schwinger, end of the subsection on an “old quarrel” in november 1911 Poincaré had no source of a familiar cartoon about the Higgs beautifully designed graphics. My most Tom Kibble at 80 Stanisław M Ulam and others. with einstein – and in my view this is appreciation of the subtle nature of einstein’s boson. Only after failing to fi nd the answer memorable scene is the moment of the fi rst By Jerome Gauntlett (ed.) While some of the papers address inaccurate. What i know from having revolutionary work. Poincaré, who worked via Google, did i remember that Grupen LHc collisions, where Levinson’s use of World Scientifi c problems in the philosophy of physics and read some of Poincaré’s research papers is on the generalized Lorentz transformations, draws cartoons – and, yes, it was one of his. music and kaleidoscopic imagery leaves the Hardback: £38 in physics and society that are timeless that it was Lorentz who was castigated by does not mention e = mc2, arguably the Probably better known as a physicist and audience captivated by the almost spiritual Paperback: £18 in nature, the symposium has a further Poincaré for “needing fi ve pages where fi ve most famous equation, published six years author of a number of textbooks, for example, exaltation of this scientifi c achievement. E-book: £14 signifi cance. It took place at a historic words suffi ce” (I paraphrase). The situation previously. By 1911 Poincaré had created the on astroparticle physics (CERN Courier This US fi lm-maker aiming at a US Tom Kibble – recently knighted juncture of particle physics – the emergence with einstein seemed more complex. Here tools that were needed to prove e = mc2 in January/February 2006 p54), he also has audience has, inevitably, made an American (p36) – is an inspirational of the Standard Model as the result of i was seeking clarity. everybody “knows”, more abstract mathematical terms, and yet a talent for sketching, and so could create fi lm, with gutsy postdoc Monica and theoretical physicist who has experiments that pointed to the existence of and therefore in accord with diplomatic he showed no interest in following einstein’s his own amusing visuals to accompany his self-assured theorists. A great deal of the made profound contributions quarks. Some of the papers refl ect both the traditions, this book avoids any explicit footsteps. Why? lectures. He has now assembled a range of his fi lm is dominated by American accents, so to the understanding of the pre-quark and post-quark points of view. mention of what is, in my opinion, the With the two pivotal issues – Henri output in this small book published by Siegen much so that i felt that the international spirit physical world. This book For these reasons, these proceedings merit historical-context issue of importance. Poincare’s relation to the family’s political university, where he has been professor of of cern became somewhat neglected. is a compilation of papers based on the reissue and re-examination.
48 49 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier July/August 2014 Viewpoint cividec Instrumentation
CIVIDEC Instrumentation is a R&D company born from the cutting-edge technology of CERN. We specialise in turn-key The strength of worldwide collaboration solutions for beam diagnostics based on CVD diamond technology.
Physicists from across the of the detectors. Those of us from richer countries should not forget that! Diamond Detectors globe bring a welcome richness of course an experiment like ATLAS could not have been built without the to the LHC experiments. massive and leading contributions from cern’s member states and other large, highly industrialized countries, and we experimentalists must be grateful for their The enthusiasm and support in the fi rst place. They are the motivation to explore particle backbone that made it possible to be open to physics at the high-energy other countries that have great human talent frontier knows no borders but little in the way of material resources. between the nations and regions of the The years immediately following the planet. it is shared between physicists of ATLAS and cMS Letters of intent in widely different cultures and origins. This is october 1992 were a time when the two evident today when looking around the large collaborations grew most rapidly in terms of but still overcrowded auditoria where the people and institutes (CERN Courier June latest results from the LHc are presented, as 2013 p22). The spokespersons made many with the announcements of the Higgs-boson trips to far-fl ung, non-European countries discovery (CERN Courier September 2012 to motivate and invite participation and NEW: Diamond Beam Position Monitor p43). Such results are, in turn, presented by Peter Jenni in the ATLAS cavern. (Image contributions to the experiments, in parallel speakers on behalf of LHc collaborations credit: Claudia Marcelloni.) (and sometimes even in competition) with that span the globe, with physicists from all cern’s effort to enlist non-member-state • Beam Loss Monitors inhabited continents. such as russia (still the Soviet union in the contributions to enable the timely Our beam loss monitors are radiation hard and provide bunch-by-bunch loss information with 1 ns time resolution. Today we take this for granted, but it is beginning), eastern europe and Japan, and construction of the accelerator. it was worth remembering that it took about two later across the world. My “hat” changed during this period that the current healthy • Alpha-Spectroscopy decades to grow and consolidate these quickly from predominantly cern to mix of wealthy and less-wealthy countries We provide state-of-the-art solutions for alpha-spectroscopy with excellent energy resolution and gamma back- worldwide scientifi c and human projects into ATLAS from the early 1990s, and the focus was established in the two collaborations, ground rejection. the peaceful, creative and effi cient networks moved from generic LHc detectors and placing value clearly not only on material that are now exploring LHc physics. physics to a concrete experiment project. contributions but also on intellectual ones. • Fast-Neutron Monitors This process of collaboration building A formidable evolution took place during The building up and consolidation of Fast neutrons in the MeV range are monitored with our diamond technology in combination with our fast is of course not fi nished yet, and many the past 25 years, which was a pleasure to collaboration with continents in the Southern challenges remain. cern and its experiment see. Presenting the LHc and ATLAS in hemisphere is, in general, more recent, precision electronics. collaborations at the LHc’s predecessors the early years could be quite an adventure. and has benefi ted, for example in the case Thermal-Neutron Monitors – the Large electron–Positron collider and There were places where electricity for the of Latin America, from european union • the Super Proton Synchrotron p–p collider – slides was not always guaranteed, many exchange programmes, which in particular We provide solutions for thermal-neutron monitors using Lithium-converters. have long been a fertile cradle for physicists colleagues from potential new collaboration have brought many bright students to the Electronics teaming up from different regions (CERN partners barely spoke any english, and the experiments (CERN Courier June 2014 p58). • Courier March 2014 p23 and April 2014 local custom could be that only the most Yet, there is a long way to go in Africa, with – Broadband Current Amplifi er (2 GHz, 40 dB) for beam loss and timing applications. p16), but with the LHc collaborations, senior professor would be expected to speak many talented people eager to join the great – Fast Charge Amplifi er for particle counting and fast spectroscopy. globalization for the experiments has up. Today one may fi nd, at the same places, LHc adventure. of course fundamental – Spectroscopic Shaping Amplifi ers for precision spectroscopy. reached a new scale. roughly speaking, the most modern conference installations physics is our mission, but personally i am about half of the participants in ATLAS and and – even more enjoyable to see – confi dent, also convinced that attracting young people • Readout Systems cMS are from non-member states of cern. clever young students and postdocs into science will help society in all regions, Digital readout system ROSY® -- 5 GS/s -- FPGA real-time processing -- Linux server. i consider it a big privilege to have expressing their curiosity and opinions. ultimately. So cern with the LHc, which witnessed this evolution from inside cern What was also striking in the early times from the early dreams now spans half of the and actively from inside the ATLAS was the great motivation to be part of the organization’s 60 years, can also be proud of collaboration – and to have been able, experiment collaborations and to contribute contributing a seed to building up a peaceful humbly, to contribute to it a little. For me, – sometimes under diffi cult conditions – to global society. For me personally, besides the fi rst contacts with far-away countries the building up of the experiments. i often the physics, the LHc has also brought many WE PIONEER CUSTOMIZED SOLUTIONS started with several visits as a junior member had the impression that colleagues in less friends across the world. of cern delegations in the late 1980s and privileged countries made extraordinary ● Peter Jenni, Albert-Ludwigs-University Freiburg early 1990s, presenting the LHc dream to efforts, with many personal sacrifi ces, to and CERN, spokesperson for ATLAS until February colleagues and decision makers in places fulfi l their promises for the construction 2009. CIVIDEC Instrumentation GmbH | Vienna Schottengasse 3A/1/41 | A-1010 Vienna, Austria | phone: +43 1 9229307 | contact: [email protected] | www.cividec.at | 50 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CAEN Electronic Instrumentation
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June.indd 1 30/06/14 06:48 cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 CERN Courier December 2012 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 January and August. The views expressed are not necessarily those of the CERN cerncourier management.
Editor Christine Sutton V o l u m e 5 2 N u m b e r 1 0 D e C e m b e r 2 0 1 2 News editor Kate Kahle Editorial assistant Carolyn Lee CERN, 1211 Geneva 23, Switzerland E-mail [email protected] 5 N E W s Fax +41 (0) 22 785 0247 Web cerncourier.com • De-squeezed beams for ALFA and TOTEM • The Republic of Cyprus becomes CERN associate member state First results from Advisory board Luis Álvarez-Gaumé, James Gillies, Horst Wenninger • proton–lead colliding beams Measurement of photons stimulates Laboratory correspondents: • Argonne National Laboratory (US) Cosmas Zachos quest for QGP temperature Leptons on the trail of the unexpected Brookhaven National Laboratory (US) P Yamin • Cornell University (US) D G Cassel CMS homes in on the heaviest quark LHCb reports fi rst 5σ DESY Laboratory (Germany) Till Mundzeck • • EMFCSC (Italy) Anna Cavallini observation of charm mixing • XMM-Newton discovers new Enrico Fermi Centre (Italy) Guido Piragino source of cosmic rays RIKEN gets clear view of element 113 Fermi National Accelerator Laboratory (US) Katie Yurkewicz • Forschungszentrum Jülich (Germany) Markus Buescher GSI Darmstadt (Germany) I Peter 10 CiENCEWatCh IHEP, Beijing (China) Tongzhou Xu s IHEP, Serpukhov (Russia) Yu Ryabov INFN (Italy) Romeo Bassoli Jefferson Laboratory (US) Steven Corneliussen 11 a s t r O W a t C h JINR Dubna (Russia) B Starchenko KEK National Laboratory (Japan) Youhei Morita Lawrence Berkeley Laboratory (US) Spencer Klein 12 a r C h i v E Los Alamos National Laboratory (US) Rajan Gupta NCSL (US) Ken Kingery Nikhef (Netherlands) Paul de Jong F E a t u r E s Novosibirsk Institute (Russia) S Eidelman Orsay Laboratory (France) Anne-Marie Lutz 15 One CP-violating phase, three beautiful results PSI Laboratory (Switzerland) P-R Kettle Saclay Laboratory (France) Elisabeth Locci Three experiments converge in their quest to measure γ. Science and Technology Facilities Council (UK) Julia Maddock SLAC National Accelerator Laboratory (US) Farnaz Khadem TRIUMF Laboratory (Canada) Marcello Pavan 19 ENLIGHT: catalysing hadron therapy in Europe
Produced for CERN by IOP Publishing Ltd As a pioneering multidisciplinary IOP Publishing Ltd, Temple Circus, Temple Way, network celebrates its 10th anniversary, Bristol BS1 6HG, UK Tel +44 (0)117 929 7481 some of the founders recall how it all
Publisher Susan Curtis started. Production editor Jesse Karjalainen Technical illustrator Alison Tovey Group advertising manager Chris Thomas 22 The three lives of DORIS: from charm quarks to cell biology Advertisement production Katie Graham DESY’s pioneering and productive ring retires. Marketing & Circulation Angela Gage Head of B2B & Marketing Jo Allen 25 Accelerators, light sources and all that jazz Art director Andrew Giaquinto A report from IPAC’12 held in New Orleans. Advertising Tel +44 (0)117 930 1026 (for UK/Europe display advertising) or +44 (0)117 930 1164 (for recruitment advertising); 28 F ACES &P LACES E-mail: [email protected]; fax +44 (0)117 930 1178
General distribution Courrier Adressage, CERN, 1211 Geneva 23, Switzerland 33 ECRUITMENT E-mail: [email protected] R In certain countries, to request copies or to make address changes, contact: China Keqing Ma, Library, Institute of High Energy Physics, PO Box 918, Beijing 100049, People’s Republic of China 37 B OOKSHELF E-mail: [email protected] Germany Veronika Werschner, DESY, Notkestr. 85, 22607 Hamburg, Germany E-mail: [email protected] 41 I NSIDE S TORY Italy Loredana Rum or Anna Pennacchietti, INFN, Casella Postale 56, 00044 Frascati, Rome, Italy E-mail: [email protected] UK Mark Wells, Science and Technology Facilities Council, Polaris House, North Star Avenue, Swindon, Wiltshire SN2 1SZ E-mail: [email protected] US/Canada Published by Cern Courier, 6N246 Willow Drive, St Charles, IL 60175, US. Periodical postage paid in St Charles, IL, US Fax 630 377 1569. E-mail: [email protected] POSTMASTER: send address changes to: Creative Mailing Services, PO Box 1147, I NTERNATIONAL J O U R N A L O F H I G H - E N E R G Y P H Y S I C S St Charles, IL 60174, US cerncourier
V O L U M E 5 2 N U M B E R 1 0 D E C E M B E R 2 0 1 2 Published by European Organization for Nuclear Research, CERN, 1211 Geneva 23, Switzerland Tel +41 (0) 22 767 61 11. Telefax +41 (0) 22 767 65 55
Printed by Warners (Midlands) plc, Bourne, Lincolnshire, UK DORIS: from charm The DORIS machine at DESY retires this year after a long career © 2012 CERN ISSN 0304-288X On the cover : to cell biology that went from particle physics to becoming a synchrotron light source, supplying experiments at HASYLAB, a dedicated laboratory on the DESY site. The image IPAC’12 CERN ENLIGHT Accelerator people Art and science: shows the Laue diffraction pattern of an enzyme called catalase, which splits get together in strange collisions NETWORK New Orleans in the library Catalysing European p25 p32 hadron therapy p19 hydrogen peroxide into water and oxygen. (Image Credit: Max Plank Society.)
3
CERN Courier December 2012 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 January and August. The views expressed are not necessarily those of the CERN cerncourier management.
Editor Christine Sutton V o l u m e 5 2 N u m b e r 1 0 D e C e m b e r 2 0 1 2 News editor Kate Kahle Editorial assistant Carolyn Lee CERN, 1211 Geneva 23, Switzerland E-mail [email protected] 5 N E W s Fax +41 (0) 22 785 0247 Web cerncourier.com • De-squeezed beams for ALFA and TOTEM • The Republic of Cyprus becomes CERN associate member state First results from Advisory board Luis Álvarez-Gaumé, James Gillies, Horst Wenninger • proton–lead colliding beams Measurement of photons stimulates Laboratory correspondents: • Argonne National Laboratory (US) Cosmas Zachos quest for QGP temperature Leptons on the trail of the unexpected Brookhaven National Laboratory (US) P Yamin • Cornell University (US) D G Cassel CMS homes in on the heaviest quark LHCb reports fi rst 5σ DESY Laboratory (Germany) Till Mundzeck • • EMFCSC (Italy) Anna Cavallini observation of charm mixing • XMM-Newton discovers new Enrico Fermi Centre (Italy) Guido Piragino source of cosmic rays RIKEN gets clear view of element 113 Fermi National Accelerator Laboratory (US) Katie Yurkewicz • Forschungszentrum Jülich (Germany) Markus Buescher GSI Darmstadt (Germany) I Peter 10 CiENCEWatCh IHEP, Beijing (China) Tongzhou Xu s IHEP, Serpukhov (Russia) Yu Ryabov INFN (Italy) Romeo Bassoli Jefferson Laboratory (US) Steven Corneliussen 11 a s t r O W a t C h JINR Dubna (Russia) B Starchenko KEK National Laboratory (Japan) Youhei Morita Lawrence Berkeley Laboratory (US) Spencer Klein 12 a r C h i v E Los Alamos National Laboratory (US) Rajan Gupta NCSL (US) Ken Kingery Nikhef (Netherlands) Paul de Jong F E a t u r E s Novosibirsk Institute (Russia) S Eidelman Orsay Laboratory (France) Anne-Marie Lutz 15 One CP-violating phase, three beautiful results PSI Laboratory (Switzerland) P-R Kettle Saclay Laboratory (France) Elisabeth Locci Three experiments converge in their quest to measure γ. Science and Technology Facilities Council (UK) Julia Maddock SLAC National Accelerator Laboratory (US) Farnaz Khadem TRIUMF Laboratory (Canada) Marcello Pavan 19 ENLIGHT: catalysing hadron therapy in Europe
Produced for CERN by IOP Publishing Ltd As a pioneering multidisciplinary IOP Publishing Ltd, Temple Circus, Temple Way, network celebrates its 10th anniversary, Bristol BS1 6HG, UK Tel +44 (0)117 929 7481 some of the founders recall how it all
Publisher Susan Curtis started. Production editor Jesse Karjalainen Technical illustrator Alison Tovey Group advertising manager Chris Thomas 22 The three lives of DORIS: from charm quarks to cell biology Advertisement production Katie Graham DESY’s pioneering and productive ring retires. Marketing & Circulation Angela Gage Head of B2B & Marketing Jo Allen 25 Accelerators, light sources and all that jazz Art director Andrew Giaquinto A report from IPAC’12 held in New Orleans. Advertising Tel +44 (0)117 930 1026 (for UK/Europe display advertising) or +44 (0)117 930 1164 (for recruitment advertising); 28 F ACES &P LACES E-mail: [email protected]; fax +44 (0)117 930 1178
General distribution Courrier Adressage, CERN, 1211 Geneva 23, Switzerland 33 ECRUITMENT E-mail: [email protected] R In certain countries, to request copies or to make address changes, contact: China Keqing Ma, Library, Institute of High Energy Physics, PO Box 918, Beijing 100049, People’s Republic of China 37 B OOKSHELF E-mail: [email protected] Germany Veronika Werschner, DESY, Notkestr. 85, 22607 Hamburg, Germany E-mail: [email protected] 41 I NSIDE S TORY Italy Loredana Rum or Anna Pennacchietti, INFN, Casella Postale 56, 00044 Frascati, Rome, Italy E-mail: [email protected] UK Mark Wells, Science and Technology Facilities Council, Polaris House, North Star Avenue, Swindon, Wiltshire SN2 1SZ E-mail: [email protected] US/Canada Published by Cern Courier, 6N246 Willow Drive, St Charles, IL 60175, US. Periodical postage paid in St Charles, IL, US Fax 630 377 1569. E-mail: [email protected] POSTMASTER: send address changes to: Creative Mailing Services, PO Box 1147, I NTERNATIONAL J O U R N A L O F H I G H - E N E R G Y P H Y S I C S St Charles, IL 60174, US cerncourier
V O L U M E 5 2 N U M B E R 1 0 D E C E M B E R 2 0 1 2 Published by European Organization for Nuclear Research, CERN, 1211 Geneva 23, Switzerland Tel +41 (0) 22 767 61 11. Telefax +41 (0) 22 767 65 55
Printed by Warners (Midlands) plc, Bourne, Lincolnshire, UK DORIS: from charm The DORIS machine at DESY retires this year after a long career © 2012 CERN ISSN 0304-288X On the cover : to cell biology that went from particle physics to becoming a synchrotron light source, supplying experiments at HASYLAB, a dedicated laboratory on the DESY site. The image IPAC’12 CERN ENLIGHT Accelerator people Art and science: shows the Laue diffraction pattern of an enzyme called catalase, which splits get together in strange collisions NETWORK New Orleans in the library Catalysing European p25 p32 hadron therapy p19 hydrogen peroxide into water and oxygen. (Image Credit: Max Plank Society.)
3
CERN Courier December 2012 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 January and August. The views expressed are not necessarily those of the CERN cerncourier management.
Editor Christine Sutton V o l u m e 5 2 N u m b e r 1 0 D e C e m b e r 2 0 1 2 News editor Kate Kahle Editorial assistant Carolyn Lee CERN, 1211 Geneva 23, Switzerland E-mail [email protected] 5 N E W s Fax +41 (0) 22 785 0247 Web cerncourier.com • De-squeezed beams for ALFA and TOTEM • The Republic of Cyprus becomes CERN associate member state First results from Advisory board Luis Álvarez-Gaumé, James Gillies, Horst Wenninger • proton–lead colliding beams Measurement of photons stimulates Laboratory correspondents: • Argonne National Laboratory (US) Cosmas Zachos quest for QGP temperature Leptons on the trail of the unexpected Brookhaven National Laboratory (US) P Yamin • Cornell University (US) D G Cassel CMS homes in on the heaviest quark LHCb reports fi rst 5σ DESY Laboratory (Germany) Till Mundzeck • • EMFCSC (Italy) Anna Cavallini observation of charm mixing • XMM-Newton discovers new Enrico Fermi Centre (Italy) Guido Piragino source of cosmic rays RIKEN gets clear view of element 113 Fermi National Accelerator Laboratory (US) Katie Yurkewicz • Forschungszentrum Jülich (Germany) Markus Buescher GSI Darmstadt (Germany) I Peter 10 CiENCEWatCh IHEP, Beijing (China) Tongzhou Xu s IHEP, Serpukhov (Russia) Yu Ryabov INFN (Italy) Romeo Bassoli Jefferson Laboratory (US) Steven Corneliussen 11 a s t r O W a t C h JINR Dubna (Russia) B Starchenko KEK National Laboratory (Japan) Youhei Morita Lawrence Berkeley Laboratory (US) Spencer Klein 12 a r C h i v E Los Alamos National Laboratory (US) Rajan Gupta NCSL (US) Ken Kingery Nikhef (Netherlands) Paul de Jong F E a t u r E s Novosibirsk Institute (Russia) S Eidelman Orsay Laboratory (France) Anne-Marie Lutz 15 One CP-violating phase, three beautiful results PSI Laboratory (Switzerland) P-R Kettle Saclay Laboratory (France) Elisabeth Locci Three experiments converge in their quest to measure γ. Science and Technology Facilities Council (UK) Julia Maddock SLAC National Accelerator Laboratory (US) Farnaz Khadem TRIUMF Laboratory (Canada) Marcello Pavan 19 ENLIGHT: catalysing hadron therapy in Europe
Produced for CERN by IOP Publishing Ltd As a pioneering multidisciplinary IOP Publishing Ltd, Temple Circus, Temple Way, network celebrates its 10th anniversary, Bristol BS1 6HG, UK Tel +44 (0)117 929 7481 some of the founders recall how it all
Publisher Susan Curtis started. Production editor Jesse Karjalainen Technical illustrator Alison Tovey Group advertising manager Chris Thomas 22 The three lives of DORIS: from charm quarks to cell biology Advertisement production Katie Graham DESY’s pioneering and productive ring retires. Marketing & Circulation Angela Gage Head of B2B & Marketing Jo Allen 25 Accelerators, light sources and all that jazz Art director Andrew Giaquinto A report from IPAC’12 held in New Orleans. Advertising Tel +44 (0)117 930 1026 (for UK/Europe display advertising) or +44 (0)117 930 1164 (for recruitment advertising); 28 F ACES &P LACES E-mail: [email protected]; fax +44 (0)117 930 1178
General distribution Courrier Adressage, CERN, 1211 Geneva 23, Switzerland 33 ECRUITMENT E-mail: [email protected] R In certain countries, to request copies or to make address changes, contact: China Keqing Ma, Library, Institute of High Energy Physics, PO Box 918, Beijing 100049, People’s Republic of China 37 B OOKSHELF E-mail: [email protected] Germany Veronika Werschner, DESY, Notkestr. 85, 22607 Hamburg, Germany E-mail: [email protected] 41 I NSIDE S TORY Italy Loredana Rum or Anna Pennacchietti, INFN, Casella Postale 56, 00044 Frascati, Rome, Italy E-mail: [email protected] UK Mark Wells, Science and Technology Facilities Council, Polaris House, North Star Avenue, Swindon, Wiltshire SN2 1SZ E-mail: [email protected] US/Canada Published by Cern Courier, 6N246 Willow Drive, St Charles, IL 60175, US. Periodical postage paid in St Charles, IL, US Fax 630 377 1569. E-mail: [email protected] POSTMASTER: send address changes to: Creative Mailing Services, PO Box 1147, I NTERNATIONAL J O U R N A L O F H I G H - E N E R G Y P H Y S I C S St Charles, IL 60174, US cerncourier
V O L U M E 5 2 N U M B E R 1 0 D E C E M B E R 2 0 1 2 Published by European Organization for Nuclear Research, CERN, 1211 Geneva 23, Switzerland Tel +41 (0) 22 767 61 11. Telefax +41 (0) 22 767 65 55
Printed by Warners (Midlands) plc, Bourne, Lincolnshire, UK DORIS: from charm The DORIS machine at DESY retires this year after a long career © 2012 CERN ISSN 0304-288X On the cover : to cell biology that went from particle physics to becoming a synchrotron light source, supplying experiments at HASYLAB, a dedicated laboratory on the DESY site. The image IPAC’12 CERN ENLIGHT Accelerator people Art and science: shows the Laue diffraction pattern of an enzyme called catalase, which splits get together in strange collisions NETWORK New Orleans in the library Catalysing European p25 p32 hadron therapy p19 hydrogen peroxide into water and oxygen. (Image Credit: Max Plank Society.)
3
cerncourier V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4 Contents 26 What’s next for CP violation? 5 N ew s 15 S c i encew a t c h Interest in CP violation continues today with studies of b hadrons LS1: beams are back in the Proton Synchrotron ALPHA • • 17 s t r ow a t c h and neutrinos. experiment measures charge of antihydrogen • COSY confirms A existence of six-quark states CEBAF delivers first beams 30 NOvA takes a new look at neutrino oscillations • 19 A r c h i v e following upgrade • Laser experiment simulates supernova A new experiment gets going using Fermilab’s upgraded • First direct high-precision measurement of the proton’s F e a t u r e s neutrino beam. magnetic moment sets the stage for BASE • ALICE and the 21 CP violation’s early days 35 F a ce s &P l a ce s flowing particle zoo• Higgs and top: a new window on dark A look back at a surprising discovery 50 years ago. matter ATLAS finds evidence for the rare electroweak W±W± • 43 R ec r u i t men t production • New results from ATLAS at Quark Matter 2014 23 NA31/48: the pursuit of direct CP violation • US particle-physics community sets research priorities • OECD Some background to an important result for the Standard Model. 47 B oo k s h elf report praises innovation at CERN 50 V i ewpo i n t cerncourier www. V o l u m e 5 4 N u m b e r 6 J u l y /A u g u s t 2 0 1 4