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High-Energy Nuclear Collisions and QCD Phase Structure What is the phase structure of QCD matter? - Motivations and recent results - Observables and schedule Bedanga Mohanty and Nu Xu. Phase diagram : A map shows that, at given degrees of freedom, how matter organize
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High-Energy Nuclear Collisions and QCD Phase Structure What is the phase structure of QCD matter? - Motivations and recent results - Observables and scheduleBedangaMohanty and Nu Xu
Phase diagram: A map shows that, at given degrees of freedom, how matter organize itself under external conditions. The QCDPhase diagram: structure of matter with quark- and gluon-degrees (color degrees) of freedom. Phase Diagram: Water
QCD Phase Diagram (2009) 1983 US Long Range Plan - by Gordon Baym nucl-th: 0907.4489, NPA830,709(09) L. McLerran nucl-th 0911.4806: A. Andronic, D. Blaschke, P. Braun-Munzinger, J. Cleymans, K. Fukushima, L.D. McLerran, H. Oeschler, R.D. Pisarski, K. Redlich, C. Sasaki, H. Satz, and J. Stache Systematic experimental measurements (Ebeam, A) : extract numbers that may be related to the QCD phase diagram!
The QCD Phase Diagram and High-Energy Nuclear Collisions Tini, TC LHC, RHIC TE RHIC, FAIR Phase boundary RHIC,FAIR, NICA 3 2 1 quark-gluon plasma 1 Early Universe 2 3 TC TE Critical Point? Temperature hadron gas CSC nuclei Baryon Chemical Potential
STAR Detectors Fast and Full azimuthal particle identification EMC+EEMC+FMS (-1 ≤ ≤ 4) TPC TOF DAQ1000 HFT 2013 FGT 2011 BNL PAC, 21 - 22, 2010 MTD 2013
TOF Performance √sNN = 39 GeV Au + Au Collisions TPCTPC+ToF
PID: 7.7, 39, 200 GeV (π±, K±, p) Au+Au at 7.7 GeV Au+Au at 39 GeV Au+Au at 200 GeV
(I) Partonic Collectivity at RHIC PHENIX: nucl-ex/0604011 STAR: preliminary QM09: arXiv 0907.2265 Low pT(≤ 2 GeV/c): hydrodynamic mass ordering High pT (> 2 GeV/c): number of quarks ordering s-quark hadron: smaller interaction strength in hadronic medium light- and s-quark hadrons: similar v2 pattern => Partonic Collectivity at RHIC !
Observable: nq Scaling of v2 • m ~ mp ~ 1 GeV • ss not K+K- • h<< p, • In the hadronic case: • No number of quark scaling • Very small value of v2 !
High Order Correlations Event by event: net-proton Kurtosis Kp(E)* two proton correlation functions C2(E) ratio of the d/p ratio of K/p * Gavai and Gupta, 03, 05; Gupta 0909.4630 M. Cheng et al. 08 Gupta, Karsch, Stephanov, INT, 08
Observable: High Moments STAR: 1004.4959, PRL in print High moments are more sensitive to critical point related fluctuation. The 4th moment, Kurtosis, is directly related to the corresponding thermodynamic quantity: susceptibility for conserved quantum numbers such as Baryon number, charge, strangeness…
L or B Observable: LPV Parity even observable STAR; PRL 103, 251601(09); PRC 81, 54908(10). The separation between the same-charge and opposite-charge correlations. - Strong external EM field - De-confinement and Chiral symmetry restoration Beam Energy Dependence & U+U
Slope Parameter Systematics Student Lecture, “Quark Matter 2006”, Shanghai, Nov. 14 - 20, 2006
Di-leptons allow us to measure the direct radiation from the matter with partonic degrees of freedom, no hadronization! • Low mass region: • , , e-e+ • minve-e+ • medium effect • Chiral symmetry • -Intermediateregion: • J/e-e+ • minve-e+ • Direct radiation Expanding partonic matter at RHIC and LHC! Observable: Direct Radiation (M ≥ 1) Direct radiation: hadronic partonic
Maximum Baryon Density The maximum baryon density at freeze-out: √sNN ~ 8 GeV Both K+/π and Λ/π ratios reach maximum at this energy
DOE New RHIC Performance Milestones spin Heavy ion
1) At 200 GeV top energy - Study medium properties, EoS - pQCD in hot and dense medium 2) RHIC beam energy scan (BES) - Search for the QCD critical point - Chiral symmetry restoration STAR Physics Focus Forward program - Study low-x properties, initial condition, search for CGC - Study elastic and inelastic processes in pp2pp Polarized p+p program - Study proton intrinsic properties