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LHC 加速器における 高エネルギー原子核衝突実験 志垣 賢太 (, ALICE Collaboration ) 京都大学基礎物理学研究所研究会 “ 熱場の量子論とその応用 ” 2011 年 8 月 22 日 於 京都大学.

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Presentation on theme: "LHC 加速器における 高エネルギー原子核衝突実験 志垣 賢太 (, ALICE Collaboration ) 京都大学基礎物理学研究所研究会 “ 熱場の量子論とその応用 ” 2011 年 8 月 22 日 於 京都大学."— Presentation transcript:

1 LHC 加速器における 高エネルギー原子核衝突実験 志垣 賢太 (, ALICE Collaboration ) 京都大学基礎物理学研究所研究会 “ 熱場の量子論とその応用 ” 2011 年 8 月 22 日 於 京都大学

2 Topicalities in Experimental Search for Hot and Dense Partonic Matter 京都大学基礎物理学研究所研究会 「熱場の量子論とその応用」 2003 年 8 月 20-22 日 京都大学基礎物理学研究所 志垣 賢太 広島大学 / PHENIX Collaboration

3 August 22, 2003 Topicalities in Experimental Search for Hot and Dense Partonic Matter / K.Shigaki 2 - Presentation Outline -  physics goals of relativistic heavy ion programs  achieved programs at BNL-RHIC Au+Au, d+Au and p+p up to  s NN = 200 GeV hadron suppression at high p t (jet quenching) modification of angular correlations  ongoing/near-future programs at BNL-RHIC high statistics Au+Au (and p+p) heavy quark states (color Debye screening) low-mass dileptons (chiral restoration) direct photons (thermal radiation) more systematics with A and energy scans  future programs at CERN-LHC strategies, expectations and ongoing activities

4 August 22, 2003 Topicalities in Experimental Search for Hot and Dense Partonic Matter / K.Shigaki 3 - Where are We ? What is Next ? -  quark-gluon plasma discovered ? “it’s a quark-gluon plasma. period.” (M.Gyulassy) maybe premature to claim triumph  further insights expected via rare processes probe of deconfinement heavy quark states: J/ ,  ’ penetrating probes of medium dileptons: e  e ,     direct photons  these measurements planned in next Au+Au run

5 August 22, 2003 Topicalities in Experimental Search for Hot and Dense Partonic Matter / K.Shigaki 4 - LHC Status and Plan -  accelerator on its way startup in 2007 confirmed in June, 2003, CERN council p+p commissioning in April 2007 heavy ion pilot run by end of 2007  wish list as of June 2002 initial few years regular p+p runs at  s = 14 TeV, L ~ 10 29 and < 3  10 30 cm -2 s -1 2 - 3 years of Pb+Pb at L ~ 10 27 cm -2 s -1 1 year of p/d/  +Pb at L ~ 10 29 cm -2 s -1 1 year of light ions at L ~ few 10 27 - 10 29 cm -2 s -1

6 August 22, 2003 Topicalities in Experimental Search for Hot and Dense Partonic Matter / K.Shigaki 5 - Summary and Concluding Remarks -  first round of RHIC physics programs completed study of QCD in extreme conditions and scales especially high energy density frontier medium with strong final state effects formed in central Au+Au collisions observed via jet quenching and its absence in d+Au can be quark-gluon plasma; not conclusive yet  coming high statistics run(s) essential and exciting additional probes of medium to be investigated baseline established for J/  measurement light vector mesons also noteworthy direct photons, unclear at SPS, to soar at RHIC/LHC  RHIC presenting rich harvest; LHC getting ready even more fruitful physics ahead of us

7 expeditions in thermal field at LHC –QCD phase boundary crossed already at RHIC newly started LHC/ALICE physics programs –new regime to understand deconfined partonic matter hotter, larger, longer-lived fireball –first physics results from p+p and Pb+Pb global properties of medium hard and heavy probes of medium –thermometer at ALICE summary and concluding remarks Presentation Outline 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 6/48

8 toward deconfined partonic phase lattice Quantum Chromo-Dynamics predictions –critical temperature ~ 170 MeV –critical energy density ~ 1 GeV/fm 3 High Energy A+A Collisions Color Super-Conductivity Color-Flavor Locking Tri-Critical Point Baryon Density Energy Density (Temperature) Nucleus Deconfined Partonic Phase (Quark-Gluon Plasma) Hadron Gas Neutron Star? Critical Temperature ~ 170 MeV F. Karsch, Lect. Notes Phys. 583 (2002) 209 Expeditions on QCD Phase Diagram Early Universe 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 7/48

9 thermal radiation if in equilibrium –real and virtual thermal photons Where to Find “Thermometer” high p T : pQCD photons low p T : photons from hadronic gas intermediate p T : QGP thermal photons dominant ! also other sources plus hadron decay photons everywhere S.Turbide et al., PRC 69 014903 q qg      hadron decay photons 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 8/48

10 PRL 94, 232301 (2005) Naïve Way: Direct Real Photons measured as “excess” above hadron decay photon –Au+Au result consistent with pQCD×binary scaling challenging at lower p T due to smaller S/B ratio 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 9/48

11 low mass electron-positron pairs p+p: hadronic decay + pQCD photon at high p T Au+Au: enhancement above ~ 135 MeV –no  0 decay virtual photon above  0 mass Alternative: “Almost Real” Photons PHENIX (A. Adare et al.), PRL 104, 132301 (2010) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 10/48

12 real and virtual photon methods consisitent p+p data consistent with pQCD down to low p T Au+Au above scaled pQCD at low p T –excess ~ exponential with 221  19  19 MeV NLO pQCD (W. Vogelsang) Direct Photon Spectra via  and  * PHENIX (A. Adare et al.), PRL 104, 132301 (2010) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 11/48

13 initial temperature > data slope ~ 220 MeV 300–600 MeV from models –hydro-dynamical models describing data within factor of 2 –w/  0 = 0.15–0.6 fm/c cf. phase transition predicted at ~ 170 MeV Initial Temperature Evaluation slope transition temperature PHENIX (A. Adare et al.), PRC 81, 034911 (2010) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 12/48

14 phase boundary: T c ~ 170 MeV,  c ~ 1 GeV/fm 3 Across the Boundary and Beyond “perfect fluid” “free gas” ? 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki RHIC 13/48

15 A Large Ion Collider Experiment ALICE CMS LHCb ATLAS, LHCf the heavy ion experiment at LHC 33 countries; 116 institutes; > 1,000 members as of November, 2010 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 14/48

16 LHC run history and schedule –2009 p+p at  s = 900 GeV, 2.36 TeV –2010–2012 p+p at  s = 7 TeV (and 2.76 TeV) Pb+Pb at  s NN = 2.76 TeV –2014 full design energy –expectations in following few years p+p  s = 14 TeV, 10 31 cm  2 s  1 (ALICE), 10 7 s/y  s = 5.5 TeV, 10 31 cm  2 s  1, 10 6 s/y×1 y Pb+Pb  s NN = 5.5 TeV, 10 27 cm  2 s  1, 10 6 s/y p+Pb  s NN = 8.8 TeV, 10 29 cm  2 s  1, 10 6 s/y×1 y Ar+Ar  s NN = 6.3 TeV, 10 29 cm  2 s  1, 10 6 s/y×1 y LHC Run History and Plan 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 15/48

17 ALICE 2010 p+p data taking –> 800 M interactions –> 100 M muon triggers for J/  –> 25 M high multiplicity triggers The Highest Baseline, 7 TeV p+p 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 16/48

18 anti-proton/proton ratio in mid-rapidity region –0.957  0.006 (stat)  0.014 (sys) at 900 GeV –0.990  0.006 (stat)  0.014 (sys) at 7 TeV Almost Zero Baryo-Chemical Potential ALICE (K. Aamodt et al.), PRL 105, 072002 (2010) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 17/48

19 e.g. closed/open heavy flavors –J/ , D 0, D , D  Vital Reference in New Energy Domain J/       J/   e  e  2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 18/48

20 2.76 TeV Pb+Pb from 07.11.2010–06.12.2010 –14 times higher  s NN than at RHIC First Pb+Pb Run in Late 2010 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 19/48

21 ~ 10  b  1 delivered; > 90 M recorded in total –3% of nominal luminosity (10 27 cm  2 s  1 ) at end of run –~ 3×initial expectation ALICE 2010 Pb+Pb Data Taking 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 20/48

22 first physics results within a few weeks into run ATLAS, CMS Having Fun, Too 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 21/48

23 dN ch /d  = 1580  80 (sys) –high side of predictions –faster growth with  s than in p+p i.e.  s dependent nuclear amplification Charged Particle Multiplicity Density back at RHIC 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki ALICE (K. Aamodt et al.), PRL 106, 032301 (2011) 22/48

24 ~ 2.5×transverse energy density than at RHIC from Bjorken formula:  0 ~ 16 GeV/fm 2 c ~ 3×at RHIC –lower limit for  ; likely higher with shorter time scale Initial Energy Density 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 23/48

25 p+p 7 TeV Pb+Pb 2.76 TeV radius ~ 1/width Enhancement Pair Momentum Difference Hotter, Larger, Longer-Lived Fireball ALICE (K. Aamodt et al.), PLB 696, 328 (2011) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki Bose Einstein (aka HBT) particle interferometry –space-time evolution of co-moving volume lifetime also accessible via Fourier transformation (E, p)  ( , x) –particle multiplicity dependences consistent with models ~ 2×larger, 20–30% long-lived than at RHIC –~ 300 fm 3, ~ 10 fm/c 24/48

26 strongly coupled medium found at RHIC –large elliptic azimuthal anisotropy (v 2 ) p T averaged v 2 increase by 30% at LHC Still Strongly Coupled (as at RHIC)? 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki ALICE (K. Aamodt et al.), PRL 105, 252302 (2010) 25/48

27 consistent at LHC and RHIC within uncertainties –  s NN = 2.76 TeV and 200 GeV 30% increase explained by higher mean p T –higher freeze out temperature? –stronger collective radial expansion? p T Differential Azimuthal Anisotropy 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki ALICE (K. Aamodt et al.), PRL 105, 252302 (2010) 26/48

28 Collective Radial Expansion 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki , K, p common blast wave fit mean p T rise, especially for heavier particles –no scaling behavior with particle multiplicity density smooth kinematic connection assuming blast wave –superposition of thermal emission + radial expansion –stronger radial expansion at LHC 27/48

29 much harder and abundant jets than at RHIC ~ 10×charming and ~ 100×beautiful than at RHIC –powerful probes with known mass and color charge charm/beauty  NN (mb)shadowingmultiplicity p+p 14 TeV11.2/0.5 1.0/1.00.16/0.007 central Pb+Pb 6.6/0.20.65/0.85 115/4.6 Powerful Hard/Heavy Probes at LHC 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 28/48

30 quark/gluon energy loss in partonic matter –first signature of hot and dense matter at RHIC jet energy imbalance in single events –new at LHC! full statistics analysis in progress –ALICE uniquely capable to include low p T particles     Jet Quenching and Mono-Jet hadrons (jet) high p T hadron hadrons (jet) high p T hadron quark (anti-)quark quenched jet 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 29/48

31 Ev.-by-Ev. Di-Jet Asymmetry (ATLAS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki see also ATLAS (G. Aad et al.), PRL 105, 252303 (2010) full jet reconstruction with anti-k T clustering energy asymmetry asymmetric jets in central collisions 30/48

32 full jet reconstruction with iterative cone clustering Ev.-by-Ev. Di-Jet Asymmetry (CMS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki CMS (S. Chatrchyan et al.), arXiv:1102.1957 [nucl-ex] (2011) 31/48

33 angular correlation maintained fragmentation as in vacuum Jets (Quenched but) Barely Modified 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki see also ATLAS (G. Aad et al.), PRL 105, 252303 (2010) CMS-PAS-HIN-11-004 32/48

34 consistent with picture of: –strong out-of-cone energy loss –remnant parton fragmentation in vacuum Energy Widely Re-Distributed (CMS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki CMS (S. Chatrchyan et al.), arXiv:1102.1957 [nucl-ex] (2011) 33/48

35 normalization including CDF data normalization by 0.9 TeV ×NLO (2.76 TeV) / NLO (0.9 TeV) Singles to Probe Quark Energy Loss LHC-ALICE charged particles RHIC-PHENIX  0 ALICE (K. Aamodt et al.), PLB 696, 30 (2011) particle yields suppressed at high p T quantified with “nuclear modification factor” –similar overall trend at LHC and RHIC minimum value ~1.5 times smaller rising with p T ; newly clear at LHC 2.76 TeV p+p reference collected in 2011 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 34/48

36 direct prompt photon expecting no suppression identified with isolation and shower shape no nuclear modification seen Colorless Reference (CMS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki CMS-PAS-HIN-11-002 35/48

37 maximum suppression by factor ~ 7 at ~ 7 GeV/c preliminary Inclusive Charged Hadron R AA 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki CMS-PAS-HIN-10-005 see also ALICE (K. Aamodt et al.), PLB 696, 30 (2011) 36/48

38 central/peripheral ratio ~ 0.5 –consistent with single particle suppression Jet Yield Suppression (ATLAS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki R = 0.4 R = 0.2 37/48

39 baryon/meson difference as at RHIC still vital probe for parton energy loss systematics Identified Hadron Suppression 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki  ,  0 K 0 s,  38/48

40 Open Charm Suppression 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki D +       charm behaving similarly with lighter quarks systematic measurements and theory comparison –gluon/quark; Casimir factors? –light/heavy; dead cone effect? 39/48

41 accessible to charm and beauty energy loss –higher p T leptons mainly from beauty beauty also strongly suppressed? Heavy Flavor via High p T Leptons 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 40/48

42 non prompt (off vertex) J/  from B decay prompt and non prompt J/  suppressed at high p T potential discretion between charm and beauty Beauty Quark Quenching (CMS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki CMS-PAS-HIN-10-006 41/48

43 Closed Heavy Flavor Suppression 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki J/  suppression as a signature of deconfinement –observed at RHIC and SPS; interpretation ambiguous –  and its sub-states key to resolve mechanism competing mechanisms –melting, recombination, feed down, … 42/48

44 J/  Suppression at LHC 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki J/  R AA at 2.76 TeV and 0.2 TeV always note kinematic differences –(pseudo-)rapidities, transverse momentum ranges 43/48

45 higher resonances expected to melt earlier  (1s) suppressed by 0.6  0.15  (2s, 3s) further suppressed; 2.4  effect Higher  States Suppression (CMS) 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki CMS-PAS-HIN-10-006 CMS-PAS-HIN-11-007 CMS (S. Chatrchyan et al.), arXiv:1105.4894 [nucl-ex] (2011) 44/48

46 e.g. anti-nuclei … and even more exotics, e.g. anti-hyper-nuclei More Fun Stuffs, Too ~ 2 M minimum-bias Pb+Pb 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 45/48

47 ALICE photon spectrometer: PHOS –photons, nuetral mesons, jet tagging + L0, L1 trigger capability wide coverage from 100 MeV to 100 GeV –high eneregy resolution, high granularity  /E ~ 3 %/  E up to 100 GeV PbWO 4 crystals of 22 (1.0 R Moliere )×22×180 (20 X 0 ) mm 3 APD + charge sensitive pre-amplifier readout cooled and controlled at  25  0.1  C –|  | < 0.12,  = 100  at 4.6 m 56×64×5 modules; 17,920 channels, 12.5 t –3 (/5) modules in operation Thermal Photon Hunting at ALICE thermal ~ e  E/T hadron decays jet-medium interaction jet-photon conversion bremsstrahlung pQCD processes ~ p T  n compton scattering annihilation fragmentation 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 46/48

48 nuclear physics program at LHC now in full glory hotter, larger, longer-lived fireball than at RHIC –~ 3 (or more)  higher initial energy density –~ 2  larger and 20–30% longer lived at freeze out smooth kinematic connection of soft observables surprises and theory challenges in hard probes –hadron spectra further modified –heavy quark similarly suppressed at higher p T first direct measurements of beauty and  suppression –strong di-jet energy imbalance and out-of-cone radiation regime to understand deconfined partonic matter! Summary and Concluding Remarks 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 47/48

49 symposium at JPS fall 2011 in Hirosaki –session 17pSJ: 9/17 (Sat.) afternoon –followed by QCD matter open forum informal meeting WPCF’11 (Hongo, Tokyo, 9/20–24) ISMD’11 (Miyajima, Hiroshima, 9/26–30) special thanks to A. Morsch (ALICE) –many slides inspired by his PLHC’11 presentation Final Notes and Acknowledgement 2011/8/22 TQFT’11 – High Energy Nuclear Collision Experiments at LHC – K.Shigaki 48/48


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