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Partonic EoS in High-Energy Nuclear Collisions

Partonic EoS in High-Energy Nuclear Collisions. Nu Xu Lawrence Berkeley National Laboratory Many thanks to the conference organizers. Outline. Introduction Bulk properties - partonic collectivity from multi-strange hadrons - hint of charm collectivity Summary. QCD Phase Diagram.

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Partonic EoS in High-Energy Nuclear Collisions

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  1. Partonic EoS inHigh-Energy Nuclear Collisions Nu XuLawrence Berkeley National Laboratory Many thanks to the conference organizers “ATHIC 2006” June 29 - July 1, 2006

  2. Outline • Introduction • Bulk properties - partonic collectivity frommulti-strange hadrons - hint of charm collectivity • Summary “ATHIC 2006” June 29 - July 1, 2006

  3. QCD Phase Diagram “ATHIC 2006” June 29 - July 1, 2006

  4. LGT Predictions 1) Large increase in  a fast cross cover ! • 2) Does not reach ideal, • non-interaction S. Boltzmann • limit ! • many body interactions • Collective modes • Quasi-particles are necessary 3) TC~ 170 MeV robust! • Z. Fodor et al, JHEP 0203:014(02) • Z. Fodor et al, hep-lat/0204001 • C.R. Allton et al, hep-lat/0204010 • F. Karsch, Nucl. Phys. A698, 199c(02). Lattice calculations predict TC ~ 170 MeV Strongly interacting quark-gluon Plasma - sQGP “ATHIC 2006” June 29 - July 1, 2006

  5. Hydrodynamic Flow Collectivity Local Thermalization =  Physical Goals at RHIC • Identify and study the properties of matter (EOS) with partonic degrees of freedom. • Penetrating probesBulk probes • - direct photons, leptons - spectra, v1, v2 … • - “jets” and heavy flavor - partonic collectivity • - fluctuations • jets - observed high pT hadrons (at RHIC, pT(min) > 3 GeV/c) • collectivity - collective motion of observed hadrons, not necessarily reached • thermalization among them. “ATHIC 2006” June 29 - July 1, 2006

  6. STAR Au+Au/Cu+Cu/d+Au 200 GeV QGP p+p (polarized) 200/500 GeV g “ATHIC 2006” June 29 - July 1, 2006

  7. Au + Au sNN = 200 GeV (|| < 0.75) Collision Geometry, Flow z x Non-central Collisions Number of participants:number of incoming nucleons in the overlap region Number of binary collisions:number of inelastic nucleon-nucleon collisions Charged particle multiplicity collision centrality Reaction plane: x-z plane “ATHIC 2006” June 29 - July 1, 2006

  8. ud ss uud sss Hadron Spectra from RHICp+p and Au+Au collisions at 200 GeV 0-5% more central collisions Multi-strange hadron spectra are exponential in their shapes. STAR white papers - Nucl. Phys. A757, 102(2005). “ATHIC 2006” June 29 - July 1, 2006

  9. QCD Phase Diagram “ATHIC 2006” June 29 - July 1, 2006

  10. Jet-Quenching at RHIC In central Au+Au collisions: hadrons are suppressed and back-to-back ‘jets’ disappear. Different from p+p and d+Au collisions. Energy density at RHIC:  > 5 GeV/fm3 ~ 300 Parton energy loss: Bjorken 1982 (“Jet quenching”) Gyulassy & Wang 1992 … “ATHIC 2006” June 29 - July 1, 2006

  11. Hard-soft Interactions - Thermalization STAR, nucl-ex/0501016 / PRL 95, 120301(05). Two sources of particles: - hard: hard scattering products. - soft: bulk medium constituents. - Very different as seen in peripheral. Become similar in central. near <pT> (GeV/c) Leading hadrons from away-jets away Medium from medium - PID correlation analysis - Search for signal of shock-wave. “ATHIC 2006” June 29 - July 1, 2006

  12. Anisotropy Parameter v2 coordinate-space-anisotropy  momentum-space-anisotropy y py px x Initial/final conditions, EoS, degrees of freedom “ATHIC 2006” June 29 - July 1, 2006

  13. High-Energy Nuclear Collisions • jets • J/y, D • W • f • X • L • p, K,K* • D, p • d, HBT partonic scatterings? early thermalization? Initial Condition - initial scatterings - baryon transfer - ET production - parton dof System Evolves - parton interaction - parton/hadron expansion Bulk Freeze-out - hadron dof - interactions stop Q2 TC Tch Tfo elliptic flow v2 radial flow bT time “ATHIC 2006” June 29 - July 1, 2006

  14. v2 at Low pT Region P. Huovinen, private communications, 2004 • Minimum bias data! At low pT, model result fits mass hierarchy well! • - Details does not work, need more flow in the model! “ATHIC 2006” June 29 - July 1, 2006

  15.  -mesons Flow: Partonic Flow • -mesons are very special: • they do not re-interact in hadronic environment • they are formed via coalescence with thermal s-quarks • they show strong collective flow • STAR Preliminary: QM05, M. Lemont, S. Blyth talks “ATHIC 2006” June 29 - July 1, 2006

  16. Collectivity, Deconfinement at RHIC - v2 of light hadrons and multi-strange hadrons - scaling by the number of quarks At RHIC:  mT - NQ scaling  Partonic Collectivity  Deconfinement PHENIX: PRL91, 182301(03) STAR: PRL92, 052302(04), 95, 122301(05) nucl-ex/0405022, QM05 S. Voloshin, NPA715, 379(03) Models: Greco et al, PRC68, 034904(03) Chen, Ko, nucl-th/0602025 Nonaka et al. PLB583, 73(04) X. Dong, et al., Phys. Lett. B597, 328(04). …. i ii “ATHIC 2006” June 29 - July 1, 2006

  17. STAR Preliminary STAR Preliminary Multi-strange Hadron Ratios In heavy ion collisions at RHIC, up to pT ~ 4 GeV/c, (*model predicts 8 GeV/c) the strangeness production is dominated by the thermal like processes. *Hwa and Yang, nucl-th/0602024; STAR data: QM05, SQM06 “ATHIC 2006” June 29 - July 1, 2006

  18. Blast Wave Fits: Tfo vs. < bT> 200GeV Au + Au collisions 1) p, K, and p change smoothly from peripheral to central collisions. 2) At the most central collisions, T reaches 0.6c. 3) Multi-strange particles ,  are found at higher T and lower T •  Sensitive to early partonic stage! • STAR: NPA715, 458c(03); PRL 92, 112301(04); 92, 182301(04). Multi-strange hadrons freeze-out with higher Tfo (~Tch) and smaller T “ATHIC 2006” June 29 - July 1, 2006

  19. Slope Parameter Systematics RHIC results: Collective motion for multi-strange and charm hadrons! p ≥ 0.2c SPS results: No collective motion for multi-strange and charm hadrons! At RHIC, , , , and J/ show collective motion in 200 GeV Au + Au central collisions! PHENIX (, K, p, J/): PRC69, 034909(04), QM05; STAR (, , ): QM05. “ATHIC 2006” June 29 - July 1, 2006

  20. EOS Parameters at RHIC • In central Au+Au collisions at RHIC • - partonic freeze-out: • *Tpfo = 165 ± 10 MeV weak centrality dependence • vpfo ≥ 0.2 (c) • - hadronic freeze-out: • *Tfo = 100 ± 5 (MeV) strong centrality dependence • vfo = 0.6 ± 0.05 (c) • Systematic study are needed to understand the • centrality dependence of the EOS parameters • * Thermalization assumed “ATHIC 2006” June 29 - July 1, 2006

  21. QCD Phase Diagram phase boundary? (hadronic shore) deep partonic ocean LHC RHIC-II RHIC energy scan CBM at GSI Tfo = 100±5 MeV vfo = 0.6±0.05 (c) Tpfo = 165±10 MeV vpfo ≥ 0.2 (c) “ATHIC 2006” June 29 - July 1, 2006

  22. In Au + Au collisions: • Hadron yields in the state of equilibrium - chemical freeze-out near the phase transition temperature (2) Partonic energy loss - tense interactions amongst partons, strongly interacting matter (3) Partonic collectivity and de-confinement Next step: test thermalization with heavy flavor hadrons Summary “ATHIC 2006” June 29 - July 1, 2006

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