日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 1 Low p T 領域のプローブによって 何が分かったか ? -- What we learned from low p T phenomena at RHIC? -- KANETA, Masashi 金田雅司 理研 -BNL 研究センター RIKEN-BNL Research Center

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 2 QGP Search Quark-Gluon Plasma A new state of matter under high pressure and/or temperature Existence predicted by QCD In early universe, neutron star, and relativistic heavy ion collisions Relativistic Heavy ion experiments Started from 1970’s Bevalac (LBNL), SIS(GSI), AGS(BNL), SPS(CERN) Now we have Relativistic Heavy Icon Collider (RHIC) at BNL

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 3 Relativistic Heavy Ion Collider 3.83 km circumference, 2 rings of super conducting magnet Maximum 100 GeV of Au/250 GeV of p beam, and 100GeV d beam 4 experiments PHENIX/STAR/PHOBOS/BRAHMS BRAHMS PHENIX STAR PHOBOS PHENIX event STAR event

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 4 Physics in QGP and Its Probes Parton phase deconfined A phase transition to a QGP Chiral phase transition The properties of the chiral/QGP phase Of cause, we should confirm QGP at first by probes Photon thermal radiation of hot has/QGP Lepton di-lepton : chiral transition, Debye screening by QGP charm decay : charm enhancement Hadron dynamics of the system – temperature, flow (expansion effect), baryon stopping strangeness enhancement Isospin fluctuation

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 5 Focus of This Talk Low p T phenomena Study of bulk property from matter under extremely high energy and particle density Particle abundance Expansion effect from hadronic/partonic phase Correlation of particles at final interaction space time inelastic interaction dominant elastic interaction dominant Hadron dominant Parton dominant Cartoon of space/time expansion hadron ratios p T spectra event anisotropy Key: Locally thermal equilibrated expanding system

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 6 space time inelastic interaction elastic interaction Thermal Freeze-out Chemical Freeze-out Summary of SPS Energy CERN reported on 2000/Feb/10 “A New State of Matter Created at CERN” Results from A+A collisions at  s NN ~20GeV High energy density (  =3~4GeV/fm 3, T~240MeV) J/  suppression Strangeness enhancement comparing p+p and p+A collisions Expansion of the fireball At  = 1 GeV/fm 3 (T=170~180MeV), chemical freeze-out – the final abundances of the different types of particles are fixed At  = 50 MeV/fm 3 (T= MeV ), thermal freeze-out – the hadrons stop interacting completely and the fireball freezes out Do we have a smoking gun? Low p T phenomena (soft hadron process) is established in heavy ion collisions But we want to have clear signal of thermalization,and hard probes (Jet quenching, charm excepting J/ , bottom)

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 7 Event Anisotropy The pressure gradient generates collective motion (aka flow) Central collisions radial flow Peripheral collisions radial flow andanisotropic flow x z y Momentum space Almond shape overlap region in coordinate space In Perfect Hydrodynamical source, v 2 is proportional to 

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 8 Charged hadron v 2 vs. Centrality 130GeV Au+Au collision data v 2 : elliptically Central collision region Consistent with partonic hydrodynamical source picture Reflected early stage geometry PHOBOS : PRL89(2002) GeV Au+Au peripheral central STAR : PRL86(2001)402, PRC66(2002) GeV Au+Au peripheral central hydrodynamical limit peripheral collision beam (collision) axis central collision

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 9 Energy dependence of v 2 Increasing as a function of collision energy Large v 2 in RHIC energy RQMD(v2.4) RQMD: An event generator which includes only hadronic elastic/inelastic interaction maximum

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 10 Identified hadron v 2 vs. p T Charged hadron seems to be consistent with hydrodynamical picture OK. How about identified hadrons? Hydrodynamical model can describe particle mass dependence STAR: PRL87(2001) GeV Au+Au STAR: PRL89(2002)132301

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 11 Identified hadron v 2 vs. p T p T <2GeV/c region show agreement with hydrodynamical model What happen in high p T ? Let’s wait next talk! PHENIX: nucl-ex/ GeV Au+Au central peripheral 200 GeV Au+Au STAR: nucl-ex/ central peripheral peripheral collision beam (collision) axis central collision phenix preliminary 200 GeV Au+Au p T [GeV/c] hydrodynamical model calc. New result from PHENIX  0 v 2 p T =1 to 10 GeV/c! Go to 11aSF on Sep.11 detail of v2 analysis １１ aSF 江角晋一

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 12 Statistical Model View of Particle Ratios Application of thermo-chemical model to multi hadron system J. Rafelski, Phys. Lett. B190 (1987) 167 parton-hadron phase boundary / ~1GeV, J.Cleymans and K.Redlich, PRC60 (1999) Baryon Chemical Potential  B [GeV] Neutron star central collisions The particle ratios will be described by macroscopic parameters Ideal Hadron gas (grand canonical ensemble) T ch,  B,  s and  s dilution factor for full strangeness equilibration From M.K.’s talk in the first joint meeting of JPS and DNP, Hawaii, SQM2003 SPS 130GeV 200GeV  s =0 s0s0 Full/partial Strangeness equilibration A+A at SIS to SPS, LEP, SppS  s ~ Only RHIC  s ~1 Similar approach (canonical ensemble) works for p+p(p), e + +e - collisions! [F.Becattini, EPJ C5(1998)143] Lattice QCD predictions

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 13 Full Strangeness Equilibration Centrality dependence at RHIC in 130 GeV Au+Au (and 200 GeV Au+Au central collision) Strange quark potential  s is close to zero – Close to phase boundary Relation of  s and phase boundary is discussed in PRD51 (1995) 1086 and PRC53 (1996) 1353 Approaching fully strangeness equilibration in central collisions in Au+Au collisions at RHIC –  s is 0.8 to 1.0 from peripheral to central collisions at RHIC – It is about 0.7 at AGS and SPS energy and p+p (SppS) e + +e - (LEP) collisions  B /3 M.K.’s poster for international conference Strangeness in Quark Matter 2003 peripheral central 130 GeV 200 GeV

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 14 How it works? The statistical model can describe many particle ratios by only four parameters ( T ch,  B,  s and  s )! M.K.’s poster for international conference Strangeness in Quark Matter 2003

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 15 Identified Hadron p T Distributions A common view of p T distributions for identified hadrons  Radial flow, so called Blast-wave model K* 0 STAR PRC66 (2002) (R) STAR nucl-ex/ K0sK0s K+K+ K-K- PHENIX: nucl-ex/  K+K+ K-K-  p p STAR: nucl-ex/ p p PHENIX: PRL89 (2002)  p p   STAR: PRC65 (2002) (R)   STAR: PRL89 (2002) PHENIX: nucl-ex/  STAR: nucl-ex/       Those are 130 GeV Au+Au data we have same and more results for particle species of 200 GeV Au+Au

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 16  No Boost Boosted Blast wave model E. Schnedermann et al., PRC48 (1993) 2462 p T Distributions (p T <2GeV/c) It is established from Bevalac to SPS results that The p T distributions in heavy ion collisions are not simple superimpose of p+p collisions Mass dependence Large collision system has stronger dependence Locally thermal equilibrated expanding source NA44 : PRL78 (1997) 2080

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 17 Radial Flow Effect 130 GeV Au+Au data shows Inverse slope parameter/ mass dependence increasing as a function of centrality (N part ) 200 GeV data shows same tendency Only stat. errors are shown From QM2001 talk   p PHENIX: PRL88 (2002) GeV Au+Au   p

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 18 T and flow vs. Centrality 130 GeV Au+Au 200 GeV Au+Au Centrality 0-5% 5-10% 10-20% 20-30% 30-40% 40-50% 50-60% 60-70% 70-80% p T [GeV/c] ] GeV/c) [( T T dp dy p n d  STARpreliminary Data : O. Barannikova/F. Wang QM2002 Talk Blastwave model fit for STAR data From QM2002, M.K.’s poster p T [GeV/c] KK  KK ] GeV/c) [( T T dp dy p n d  KK s STAR: nucl-ex/ Blastwave model fit for STAR data From QM2002, M.K.’s poster

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 19 Collision Energy Dependence Thermal freeze-out temperature seems to be saturate Flow velocity looks still increasing T th [GeV] [c] STAR PHENIX

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 20 All hadrons have same flow effect? Strangeness show deviation from common flow and temperature from  /K/p Same behavior at RHIC WA97: EPJ C14 (2000) 633 Inverse slope parameter T [GeV] T=T fo + m 2 STAR: nucl-ex/ line: E.Schnedermann et al. model

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 21Summary Thermodynamical and statistical models are established by SPS energy and work at RHIC well Event Anisotropy analysis suggest us the system reached early thermalization after heavy ion collisions Full strangeness equilibration only central Au+Au collision at RHIC (particle ratio) Hadronic or partonic flow? Data show large flow in event anisotropy and p T distribution It may have both hadronic (later stage) and partonic (early stage) effect. The other topics in low pT physics Bose-Einstein Correlation (11aSF 榎園昭智 ) Event-by-event fluctuation (11aSF 中村智昭 )

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 22 Backup

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 23 Baryon Stopping Power Anti-particle/particle creation is dominant in A+A collisions? BRAHMS : PRL87(2001) RHIC STAR:PRL86(2001)4778 (PRL90(2003)119903(E)) + PHENIX, PHOBOS, BRAHMS data Anti-Baryon/Baryon ratio is increasing as a function of root s NN But still not zero in RHIC energy STAR: PLB567 (2003) 167 RHIC SPS

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 24 Particle Correlation Bose/Einstein Fermi/Dirac correlation + expansion effect

日本物理学会 2003 年秋季大会 実験核物理・理論核物理合同シンポジウム QGP 探索実験の潮 流 Masashi Kaneta, RBRC 25 HBT puzzle?