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New Experimental Results from RHIC Mark D. Baker (BNL) Current and Future Directions at RHIC August 6, 2002 Many thanks to: Thomas Ullrich, Sergei Voloshin,

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Presentation on theme: "New Experimental Results from RHIC Mark D. Baker (BNL) Current and Future Directions at RHIC August 6, 2002 Many thanks to: Thomas Ullrich, Sergei Voloshin,"— Presentation transcript:

1 New Experimental Results from RHIC Mark D. Baker (BNL) Current and Future Directions at RHIC August 6, 2002 Many thanks to: Thomas Ullrich, Sergei Voloshin, Thomas Peitzmann

2 Mark D. Baker Organization Initial State “Bulk” Matter Boost (Non)-Invariance “Jet quenching”  Or failure to scale with N coll... Opacity/Explosiveness High 2002 p T puzzles Summary

3 Mark D. Baker PRL 88 (2002) 022302 Start with low entropy Final state interactions just reshuffle Multiplicity is a window on the initial state  s (GeV)

4 Mark D. Baker RHIC: N ch at mid-rapidity Consistency of RHIC results PHENIX: PC, STAR: TPC PHOBOS: Si BRAHMS: Si & Scint. A. Bazilevsky (PHENIX ) 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) QM2002 summary slide (Ullrich)

5 Mark D. Baker N ch : Centrality Dependence at RHIC (SPS) _ pp PHOBOS Au+Au |  |<1 19.6 GeV preliminary 130 GeV 200 GeV Au+Au (preliminary) M. Baker (PHOBOS) Everything counts: N ch |  =0 described nicely by KN (hard + soft)  N ch  scales with N part QM2002 summary slide (Ullrich)

6 Mark D. Baker Nch(  s NN ) – Universality of Total Multiplicity? pQCD e + e - Calculation Total charged particle multiplicity / participant pair Total particle multiplicity reflects the initial state? Note: Still interesting dynamics in the final state interactions! (A. Mueller, 1983) Same for all systems at same  s(  s eff for pp)

7 Mark D. Baker e + e - measures dN/dy T (rapidity relative to “thrust” axis) 200 GeV More detailed comparison of AA, ee

8 Mark D. Baker Understanding “Bulk” Matter Studying Matter:  Global Observables N ch,  E T ,  p T   , S, …  Particle Yields & Ratios  T ch,  B,  S, …  Particle Spectra  T fo, flow, stopping, …  Correlations  … and all that in pp, pA, AA STAR preliminary 99.5% QM2002 summary slide (Ullrich)

9 Mark D. Baker Statistical Model: First Look at AuAu @ 200 GeV All 200 GeV data taken from QM talks: F. Wang (STAR)/G. Van Buren (STAR)/ T. Chujo (PHENIX)/Ouerdane (BRAHMS) J. Lee (BRAHMS)/B. Wosiek (PHOBOS) New 130 GeV data are: C. Suire (STAR)/J. Castillo (STAR) Predictions: phenomenologically:  B ~ 1.3 GeV (1+  s/4.5 GeV) -1 assume unified freeze-out condition:  E  /  N  ~ 1.1 GeV  T QM2002 summary slide (Ullrich)

10 Mark D. Baker K-/K+ and  p/p from AGS to RHIC I. Bearden (BRAHMS) Becattini caluclation using statistical model: T=170,  s =1 (weak dependency) vary  B /T  K+/K- and  p/p K- /K+=(  p/p) 1/4 is a empirical fit to the data points K   K  driven by  s ~ exp(2  s /T)  p/p driven by  B ~ exp(-2  B /T)  s =  s (  B ) since = 0 BUT: Holds for y  0 (BRAHMS y=3) QM2002 summary slide (Ullrich)

11 Mark D. Baker Radial flow M. Kaneta/N. Xu (STAR) prediction with T th and obtained from blastwave fit (green line) prediction for T ch = 170 MeV and =0 pp no rescattering, no flow no thermal equilibrium STAR preliminary F. Wang

12 Mark D. Baker Identified Particle Spectra at RHIC @ 200 GeV Feed-down matters !!! BRAHMS: 10% central PHOBOS: 10% PHENIX: 5% STAR: 5% QM2002 summary slide (Ullrich)

13 Mark D. Baker Elliptic Flow V2V2 Normalized Multiplicity Particle asymmetry dN/d(  R ) = N 0 (1 + 2V 1 cos (  R ) + 2 V 2 cos (2(  R )) +... ) midrapidity : |  | < 1.0 STAR

14 Mark D. Baker Centrality dependence @ RHIC. STAR v 2 =0.05 130 GeV: 0.075< p t < 2.0 200 GeV: 0.150< p t < 2.0 4-part cumulants 200 GeV: 0.2< p t < 2.0 Preliminary 200 GeV: Preliminary Note possible dependence on low pt cut - Consistent results - At 200 GeV better pronounced decrease of v 2 for the most peripheral collisions. STAR Preliminary QM2002 summary slide (Voloshin)

15 Mark D. Baker v2 vs pseudorapidity Talk by S. Manly PHOBOS: No boost invariance ! QM2002 summary slide (Voloshin)

16 Mark D. Baker p + p inel. UA5, Z.Phys.C33, 1 (1986) dN/d  Systematic errors not shown 19.6 GeV is preliminary PHOBOS Au+Au dN ch /d  / 6% central Growth of Limiting Fragmentation Region

17 Mark D. Baker Interlude: Many ways to slice p z Away from mid-rapidity: Rapidity: Generalized velocity Pseudorapidity: ~y: easier to measure Feynman x: scaled p z

18 Mark D. Baker Rapidity dists.: Boost-Invariance at RHIC ? M. Baker (PHOBOS) D. Ouerdane (BRAHMS) QM2002 summary slide (Ullrich)

19 Mark D. Baker NEW: Rapidity dependence of ratios at RHIC I. Bearden (BRAHMS) BRAHMS 200 GeV At mid-rapidity: Net-protons: dN/dy  7 proton yield: dN/dy  29  ¾ of all protons from pair-production QM2002 summary slide (Ullrich)

20 Mark D. Baker Boost-Invariance at RHIC ?  Boost invariance only achieved in small region |y|<0.5  Thomas Ullrich, QM2002

21 Mark D. Baker Suppression of Hadron Production (130 GeV) ratio of p T -spectra  AA central / pp R AA < 1 for central Au+Au reactions at RHIC (130 AGeV)  observed in neutral pions and charged hadrons (PHENIX and STAR) R AA =1 for scaling with number of binary collisions J.C. Dunlop et al., Nucl. Phys. A 698, 515c (2002) K. Adcox et al., Phys. Rev. Lett. 88, 22301 (2002) QM2002 summary slide (Peitzmann)

22 Mark D. Baker Energy Dep. of p T -spectra in pp and AA spectra in pp  strong variation with beam energy  “flattening” of spectra  power law l influence of hard scattering K. Reygers et al., Hirschegg 2002 spectra in AA  little variation with beam energy  almost exponential l influence of thermal production? QM2002 summary slide (Peitzmann)

23 Mark D. Baker Preliminary  s NN = 200 GeV C. Jorgensen, BRAHMS Parallel Saturday C. Roland, PHOBOS Parallel Saturday J. Jia, PHENIX Parallel Saturday J. Klay, STAR Parallel Saturday 200 GeV results from all experiments Charged Hadron Spectra QM2002 summary slide (Peitzmann)

24 Mark D. Baker The 4 experiments Thomas Peitzmann, QM2002

25 Mark D. Baker Normalize by N part /2. Divide by the value at N part =65 PHOBOS Preliminary: Au+Au 200 GeV UA1 pp (200 GeV) Participant scaling of AuAu vs. AuAu?? C. Roland, QM2002 S. Mioduszewski, QM2002

26 Mark D. Baker Jet Evidence in Azimuthal Correlations at RHIC near-side correlation of charged tracks (STAR)  trigger particle p T = 4-6 GeV/c   distribution for p T > 2 GeV/c signature of jets also seen in  (  0 ) triggered events (PHENIX)  trigger particle p T > 2.5 GeV/c   distribution for p T = 2-4 GeV/c M. Chiu, PHENIX Parallel Saturday QM2002 summary slide (Peitzmann)

27 Mark D. Baker Counter-Jet Suppression jet suppression measure as a function of centrality trigger-jet  little modification(?) l most trigger particles from jets! counter-jet  strong suppression with increasing N part l jet quenching? inconsistencies for smaller trigger momentum  to be investigated D. Hardtke, STAR Plenary Tuesday QM2002 summary slide (Peitzmann)

28 Mark D. Baker Surface Emission? Jets ~ Npart?? How about N coll  / V ? Future measurements may clarify this... Idea from X.N.Wang, QM2002

29 Mark D. Baker Opaque expanding source would mean: Heiselberg, Levy,.PRC 59 (1999) 2716

30 Mark D. Baker High p T v 2 reaches geometric surface limit v2v2 impact parameter (fm) QM2002 (Voloshin) E. Shuryak, nucl-th/0112042 QM2002 (Filimonov, STAR)

31 Mark D. Baker Opaque, expanding source would mean: OpaqueExpanding Rischke RIKEN workshop (2002): Such strong xt correlations probably require a lack of boost-invariance...

32 Mark D. Baker kT dependence of R out /R side A. Enikizono QM2002 C.M. Kuo, QM2002 poster (PHOBOS) 200 GeV: @0.25 GeV/c

33 Mark D. Baker p/  Proton yield is comparable with pions @ 2 GeV in central collisions, less in peripheral Central p/  Peripheral Tatsuya Chujo (PHENIX)

34 Mark D. Baker High p T Puzzle I: T. Sakaguchi, PHENIX Parallel Saturday Important baryon and/or kaon contribution out to p T = 8 GeV/c? S. Mioduszewski, PHENIX

35 Mark D. Baker Adler et al., nucl-ex/0206006 High pT puzzle II: Still flowing at p T = 8 GeV/c?

36 Mark D. Baker Our state is extreme Hot dense state  Freezeout temperature near theoretical transition  High Energy Density Very black source.  v 2 ~p T and ~ maximum allowed from surface  HBT R o /R s  Approximate N part scaling of high p T particles Explosive source.  Radial flow at roughly the speed of sound  HBT R o /R s  (Unlike 2-particle correlations) Alternatively (or additionally):  Magic near-instantaneous freezeout l Blast wave or Humanic model Puzzles left at high p T

37 Mark D. Baker Oh, what one day can do... CERN baseline (17.3 GeV)PHOBOS preliminary & NA49 PbPb* WA98 (0-5%) PbPb* NA50 (0-5%) PbPb* NA50 (5-10%) PbPb EMU13 (0-9%) PbPb NA49 (0-5%) PbPb 17.3 GeV (0-5%) AuAu 19.6 GeV (0-6%)

38 Mark D. Baker Energy Density Estimate (Bj) Lattice  c  Bj  ~ 5 GeV/fm 3  Bj  ~ 25 GeV/fm 3 formation time: 0.2 - 1 fm PRL 87 (2001) 052301


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