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Heavy Ion Caf é 1 st meeting ~Experiment side~

Heavy Ion Caf é 1 st meeting ~Experiment side~. K. Ozawa Univ. of Tokyo. Signatures of QGP. (1) Average transverse momentum (2) Volume (3) Enhance of strangeness and charm (4) Enhance of anti-particles (5) Elliptic flow ( v 2 ) (6) Fluctuations conserved charges

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Heavy Ion Caf é 1 st meeting ~Experiment side~

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  1. Heavy Ion Café1st meeting ~Experiment side~ K. Ozawa Univ. of Tokyo

  2. Signatures of QGP (1) Average transverse momentum (2) Volume (3) Enhance of strangeness and charm (4) Enhance of anti-particles (5) Elliptic flow (v2) (6) Fluctuations conserved charges (7) Suppression of high-pT hadrons (8) Heavy quarkonium (9) Modification of light vector mesons (10) Thermal photons and dileptons (1) (6) (2) (7) (3) (8) (4) (9) (5) (10) K. Yagi, T. Hatsuda, and Y. Miake, “Quark-Gluon Plasma” Heavy Ion Cafe

  3. In Reality (1) Average transverse momentum (2) Volume (3) Enhance of strangeness and charm (4) Enhance of anti-particles (5) Elliptic flow (v2) (6) Fluctuations conserved charges (7) Suppression of high-pT hadrons (8) Heavy quarkonium (9) Modification of light vector mesons (10) Thermal photons and dileptons pT spectrum HBT Heavy flavor Particle ratio Elliptic flow Event-by-Event fluctuation Ratio to expectation (RAA) J/y and Y light vector mesons (r, w, f) Photons and electron pairs Near and away side Jet Heavy Ion Cafe

  4. Our activities and HI Cafe T. Chujo (M. Konno) A. Enokizono F. Kajihara and S. Sakai M. Konno (T. Chujo) H. Masui and S. Shimomura T. Nakamura T. Isobe T. Gunji and S. Oda Y. Nakamiya (and K. Ozawa) K. Ozawa pT spectrum HBT Heavy flavor Particle ratio Elliptic flow Event-by-Event fluctuation Ratio to expectation (RAA) J/y and Y light vector mesons (r, w, f) Photons and electron pairs Near and away side Jet 実際に解析をしている人に話してもらって、 各回にテーマを決めて、議論していきたい Heavy Ion Cafe

  5. A+A p+p Focus on Jet quenching • At RHIC, we can use high pT particles to diagnose the medium. • Measuring high pT particle yields: • Initial yields and pT distributions can be predicted from p+p measurements + pQCD + cold nuclear effects • Deviations can be attributed to the medium formed in A+A collisions • High pT particles (leading particles of jets) as p0, h can be measured in large BGs (dNch/dh ~ 700) Heavy Ion Cafe

  6. Observables • Yield suppression by medium effects • Comparison with p+p • Nuclear modification factor (RAA) • Light (and Heavy) mesons • Two (or three) particle correlation Heavy Ion Cafe

  7. p0, h measurements

  8. T The p+p Reference • nucl-ex/0610036 h p0 • Measurement at 200 GeV Heavy Ion Cafe

  9. nucl-ex/0610036 Initial State Effects? • New PHENIX paper on centrality dependence of p0+h in d+Au at 200 GeV • d+Au as collision system to look for initial state effects nucl-ex/0610036 => no strong initial state effects Heavy Ion Cafe

  10. p (GeV/c) T Au+Au at 200 GeV • p0 data from RHIC run 2004 Heavy Ion Cafe

  11. RAA at 200 GeV <Peripheral to Central Au+Au Collision> • Stronger Suppression for more central collision. • 0 RAA is flat for all centrality for pT>5 GeV/c. • Difference between 0 and charged increases for pT < 5 GeV/c.

  12. Au+Au at 200 GeV (h) • h data from RHIC run 2004 Heavy Ion Cafe

  13. RAA at 200 GeV (h) • h in Au+Au => Suppression by a factor of 5 in central events Heavy Ion Cafe

  14. RAA at 200 GeV • Direct g, p0 and h in Au+Au • Direct g RAA with measured p+p reference! 0-10% central events • => RAA ofhandp0consistent, both show suppression • => RAA ofgis smaller than 1 at very high pT Heavy Ion Cafe

  15. RAA at Different Energies • Comparison of p0 in Cu+Cu at 200, 62.4, and 22.4 GeV • Measured the same collision species over a broad energy range • Suppression gets larger with higher energies Heavy Ion Cafe

  16. Both behave same at mid central. RAA at Different system size Heavy Ion Cafe

  17. SPS and RHIC • Same behavior for similar Npart (63 at WA98, 67.8 at PHENIX) Blattnig parameterization used for WA98 data (S. Blattnig et. al., Phys.Rev. D62 (2000) 094030 / D. D’Enterria, Phys. Lett. B 596 (2004) 32)) Heavy Ion Cafe

  18. Summary I • Strong suppression up to 20 GeV • suppression patternsof p0 and h are similar • Clear Collision Energy dependence • Consistent results for the same system size and the same energy Do these results mean jet energy loss in the medium? Heavy Ion Cafe

  19. Comparison with models I. Vitev C. Loizides hep-ph/0608133v2 Use RAA to extract medium density: W. Horowitz I. Vitev: 1000 < dNg/dy < 2000 W. Horowitz: 600 < dNg/dy < 1600 C. Loizides: 6 < < 24 GeV2/fm Statistical analysis to make optimal use of data Heavy Ion Cafe Caveat: RAA folds geometry, energy loss and fragmentation

  20. What do we learn from RAA? GLV formalism BDMPS formalism ~15 GeV Wicks et al, nucl-th/0512076v2 Renk, Eskola, hep-ph/0610059 DE=15 GeV Energy loss distributions very different for BDMPS and GLV formalisms But RAA similar! Need more differential probes Heavy Ion Cafe

  21. Le RAA vs. Reaction Plane Au+Au collisions at 200GeV nucl-ex/0611007 Out of Plane In Plane In plane emission shows no energy loss in peripheral bins. 3<pT<5 GeV/c Heavy Ion Cafe

  22. 50-60% 0-10% RAA Le Dependence nucl-ex/0611007 Au+Au collisions at 200GeV Le = matter thickness calculated in Glauber model Little/no energy loss for Le< 2 fm Heavy Ion Cafe

  23. Heavy Flavor p+p reference: Data (converter) for pT<1.6 [GeV/c] 1.71*FONLL for pT>1.6 [GeV/c] Suppression level is the almost same as p0 and h in high pT region Heavy Ion Cafe

  24. Summary II • Several theoretical models can reproduce the experimental data. • To investigate the origin of yield suppression, need more probes • Reaction plane dependence of RAA is measured. Clear dependence on matter thickness is shown. • Measurements for Heavy flavor show the similar results in high-pT. Heavy Ion Cafe

  25. Two or Three particle correlation

  26. Trigger Associated  Associated Higher pT→ Away-side suppression Lower pT→ Away-side enhancement pT(assoc) > 2 GeV/c pT(assoc) > 0.15 GeV/c Pedestal&flow subtracted 4 < pT(trig) < 6 GeV/c STAR, PRL 91 (2003) 072304 STAR, nucl-ex/0501016  correlations at RHIC  correlations • “Trigger-associated” technique valuable for tagging jets in high-multiplicity environment (vs. jet-cone algorithms) • Probes the jet’s interaction with the QCD medium • Provides stringent test of energy-loss models Heavy Ion Cafe

  27. 8 < pT(trig) < 15 GeV/c  = Near-side IAA  = Away-side IAA IAA = Yield(0-5% Au+Au) Yield(d+Au) Dijet assoc. yields (IAA) vs. RAA STAR, Phys. Rev. Lett. 91 (2003) 072304 • Near-side yields consistent with unity • Away-side associated yields similar to RAA values Heavy Ion Cafe

  28. Centrality dependence Heavy Ion Cafe

  29. ZT Distribution • Yield in |Δφ|>0.9 • ZT = pTassoc/pTtrig Heavy Ion Cafe

  30. IAA IAA = Yield(0-5% Au+Au) Yield(d+Au) Heavy Ion Cafe

  31. Shape analysis On this figure, Shape analysis is done. Heavy Ion Cafe

  32. Away side peak shape • 3 fitting functions are used. • Shifted peak is at almost constant f. Heavy Ion Cafe

  33. D Jet Functions (PHENIX) rms, kurtosis and D also independent of pT of associated hadrons - poses challenge to color Cerenkov models nucl-ex/0611019 Heavy Ion Cafe

  34. Interpretations Gluon rad+Sudakov Mach Cone/Shock wave Cherenkov radiation T. Renk, J. Ruppert V. Koch, A. Majumder, X-N. Wang A. Polosa, C. Salgado Stöcker, Casseldery-Solana et al Also: Vitev, Phys. Lett. B630 (2005) Or large kT from radial flow or energy loss Fries, Armesto et al, Hwa Many explanations possible, need more input to conclude Heavy Ion Cafe

  35. 3-particle correlations Event by event deflection of jets Cone like structure in each event   13 13   0   0   12 12 1: 3 < pt < 4 GeV/c (Jet Tag) 2,3: 1 < pt < 2 GeV/c, 3-particle Dj-Dj probes away-side structure: Distinguish event-by-event deflection vs conical (Mercedes) emission pattern Heavy Ion Cafe

  36. Deflected Jet + Cone Elongated Away Side Jet Cone Near Side Jet - Flow Subtraction Result 13 12 Diagonal and Off-diagonal structures are suggestive of conical emission at an angle of about 1.45 radians in central Au+Au. Centrality 0-12% Heavy Ion Cafe

  37. * * * * * High pT (1) f f q Df q 13 12 12 Same Side Assoc. pTs (2,3) _ Away Side = D q* D = 3-Particle Correlations (3 particles from di-jet) + (2 from dijet + 1 other) Df*=0 Dq*=p PHENIX Preliminary Heavy Ion Cafe

  38. Df*=0 Dq*=p PHENIX Preliminary triples/trigger (A.U.) PHENIX Preliminary Correlation Topologies Normal Jet (unmodified) Df* Azimuthal Section: Deflected Jet PHENIX Simulation (scattered jet axis) Cone Jet (medium excitation) Heavy Ion Cafe

  39. Near-Side Modification 0-10% Central Cu+Cu 0-20% Central Au+Au Trigger pT IAA = CYAA/CYPP Heavy Ion Cafe

  40. d+Au, 40-100% Au+Au, 0-5% Near side Dh-Df Correlations Phys. Rev. C73 (2006) 064907 mid-central AuAu pt < 2 GeV • Near-side long range correlation in  • STAR, nucl-ex/0509030 • near side “ridge” Dr/√rref 3<pt,trigger<4 GeV pt,assoc.>2 GeV Au+Au 0-10% preliminary 0.8< pt < 4 GeV nucl-ex/0607003 See Poster by Ron Longacre 3 < pT(trig) < 6 GeV2 < pT(assoc) < pT(trig) Heavy Ion Cafe

  41. Inclusive g-h  Decay g-h contribution (via p0-hadron)  Direct g-h ! g-Jet Correlations p+p collisions at 200 GeV Heavy Ion Cafe

  42. Comparison to Pythia Heavy Ion Cafe

  43. g-Jet Correlations in AuAu Poster: M. Nguyen, N. Grau Talk: J. Jin (2.2.07) Heavy Ion Cafe

  44. Summary III • We can see a clear away side suppression in two particle correlation. • In addition, away side broadening exists. • Analysis for three particle correlation is done. It suggests conical emission. Heavy Ion Cafe

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