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What have we learned from RHIC , So far? RHIC has taken data in: 2001: AuAu (130GeV) 2002: AuAu , pp(200 GeV) 2003: pp, dAu (200 GeV) Any nucleus on any other. Top energies (each beam): 100 GeV/nucleon Au-Au. 250 GeV 2 countercirculating rings, 3.8 km circumference polarized p-p. STAR PHENIX 9 5 ° BRAHMS 30° 2.3° 30° 15° The STAR Collaboration Brazil: Universidade de Sao Paulo China: IHEP – Beijing IMP - Lanzou IPP – Wuhan USTC SINR – Shanghai Tsinghua University Great Britain: University of Birmingham France: IReS Strasbourg SUBATECH - Nantes Germany: MPI – Munich University of Frankfurt India: IOP - Bhubaneswar VECC - Calcutta Panjab University University of Rajasthan Jammu University IIT - Bombay VECC – Kolcata Poland: Warsaw University of Tech. Russia: MEPHI - Moscow LPP/LHE JINR - Dubna IHEP - Protvino U.S. Laboratories: Argonne Berkeley Brookhaven U.S. Universities: UC Berkeley UC Davis UC Los Angeles Carnegie Mellon Creighton University Indiana University Kent State University Michigan State University City College of New York Ohio State University Penn. State University Purdue University Rice University Texas A&M UT Austin U. of Washington Wayne State University Yale University Phases of QCD High Density QCD Matter in Laboratory Determine its properties QCD Prediction: Phase Transitions Deconfinement to Q-G Plasma Chiral symmetry restoration Relevance to other research areas? Quark-hadron phase transition in early Universe Cores of dense stars High density QCD Centrality and Participants in HI spectators Npart (Wounded Nucleons) ~ soft production Nbin ~ hard processes Preliminary sNN = 200 GeV peripheral (grazing shot) participants Uncorrected Centrality classes based on mid-rapidity multiplicity central (head-on) collision Triggering Capabilities •Symmetric Zero Degree Calorimeters •Central Trigger Barrel 15% Central 5% central ZDC Au Au ZDC Understanding “Bulk” Matter Studying Matter: 99.5% STAR preliminary – Global Observables Nch, ET, pT e, S, … – Particle Yields & Ratios Tch, mB, mS, … – Particle Spectra Tfo, flow, stopping, … – Correlations – … and all that in pp, pA, AA Particle Production PHOBOS Central Au+Au (200 GeV) • Multiplicity at low end of range – But: Energy density 30x nuclear matter • Most models didn’t do so well PHOBOS multiplicity papers: Compilation by K. Eskola 600 1200 Rapidity Density Phys. Rev. Lett. 85 , 3100 (2000) Phys. Rev. Lett. 87, 102303 (2001) Phys. Rev. C 65 , 31901R (2002) Phys.Rev. Lett. 88 , 22302 (2002) Phys. Rev. C 65 , 061901R (2002) nucl-ex/0210015, PRL in Press nucl-ex/0301017, subm. to PRL RHIC: Nch at mid-rapidity Consistency of RHIC results PHENIX: PC, STAR: TPC PHOBOS: Si BRAHMS: Si & Scint. PHENIX & STAR preliminary Ratio R(200/130): BRAHMS: 1.14 0.05 PHENIX: 1.17 0.03 PHOBOS: 1.14 0.05 STAR: 1.19 (no sys. yet) Nch(sNN) – Universality of Total Multiplicity? Total charged particle multiplicity / participant pair seff s / 2 Same for all systems at same s(seff for pp) • pQCD e+eNch Calculation A sB exp( C / s ) (A. Mueller, 1983) Accidental, trivial? Is plain parton fragmentation all there is in AA above s ~ 20 GeV? Nch: Centrality Dependence at RHIC (SPS) PHOBOS Au+Au |h|<1 200 GeV 130 GeV Au+Au _ pp 19.6 GeV N part dN (1 x)n pp dh 2 xnpp N coll (preliminary) preliminary Everything counts: • Nch|h=0 described nicely by KN (hard + soft) • Nch scales with Npart Rapidity Spectra: Boost-Invariance at RHIC ? M. Baker (PHOBOS) Jacobian : y ( p / m) coshh ( p ,h ) h ( p / m) 2 cosh2 h 1 D. Ouerdane (BRAHMS) ET/ Nch from SPS to RHIC PHENIX preliminary Independent of centrality Surprising fact: PHENIX preliminary Independent of energy SPS RHIC: increased flow, all particles higher pT still ET/ Nch changes very little Does different composition (chemistry) account for that? Ratios, Ratios, Ratios …. • Huge amount of results from all 4 RHIC experiments: • systematic studies of: p-/p+, K-/K+, p/p,/ ,/,/, p/p, K/p , /, /h, p, p, fK, K*/K, … – many as function of pT, Npart – at s of (20), 130, and 200 GeV – with and without feed-down correction () • BRAHMS large y coverage and reach to high pT • PHENIX reach to high pT • STAR multi-strange baryons NEW: Rapidity dependence of ratios at RHIC BRAHMS 200 GeV At mid-rapidity: Net-protons: dN/dy 7 proton yield: dN/dy 29 ¾ of all protons from pair-production p/p Central Peripheral • Proton yield is comparable with pions @ 2 GeV in central collisions, less in peripheral Statistical Model: First Look at AuAu @ 200 GeV Predictions: phenomenologically: mB ~ 1.3 GeV (1+s/4.5 GeV)-1 assume unified freeze-out condition: E/N ~ 1.1 GeV T Statistical Models: from AGS to RHIC Different implementation of statistical model (Kaneta/Nu, Beccatini, PBM et al., …) Fact: all work well at AGS, SPS and RHIC Slight variations in the models, but roughly: Fit by Beccatini using total yields from NA49 hadron gas fit with partial strangeness saturation Tch [MeV] mB [MeV] AGS 125 540 SPS 165 250 RHIC 175 30 Does the success of the model tells us we are dealing indeed with locally chemically equilibrated systems? this+flow If you ask me YES! Anisotropic flow from AGS to RHIC Picture: © UrQMD Outline: 1. Directed flow (techniques, models, results) 2. Elliptic flow (techniques, models, results) 3. Elliptic flow at high pt’s. 4. Open questions X Z b XZ – the reaction plane Anisotropic flow correlations with respect to the reaction plane dpt dy dφ dpt dy 2π ( 1 2v1 cos(φ ) 2v 2 cos( 2φ) ...) d 3N d 2N 1 Directed flow Elliptic flow What flows and when? STAR preliminary F. Wang <pT> prediction with Tth and <b> obtained from blastwave fit (green line) <pT> prediction for Tch = 170 MeV and <b>=0 pp no rescattering, no flow no thermal equilibrium and appear to deviate from common thermal freeze-out Smaller elast? Early decoupling from expanding hadronic medium? Less flow? What’s about partonic flow?