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New Experimental Results from RHIC

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. Organization. Initial State “Bulk” Matter Boost (Non)-Invariance “Jet quenching”

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New Experimental Results from RHIC

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  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. Organization • Initial State • “Bulk” Matter • Boost (Non)-Invariance • “Jet quenching” • Or failure to scale with Ncoll... • Opacity/Explosiveness • High2002 pT puzzles • Summary

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

  4. PHENIX & STAR preliminary RHIC: Nch at mid-rapidity QM2002 summary slide (Ullrich) A. Bazilevsky (PHENIX) • Consistency of RHIC results • PHENIX: PC, STAR: TPC • PHOBOS: Si BRAHMS: Si & Scint. 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)

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

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

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

  8. 99.5% Understanding “Bulk” Matter Studying Matter: • 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 STAR preliminary QM2002 summary slide (Ullrich)

  9. 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) QM2002 summary slide (Ullrich) Predictions: phenomenologically: mB ~ 1.3 GeV (1+s/4.5 GeV)-1 assume unified freeze-out condition: E/N ~ 1.1 GeV  T

  10. K-/K+ and p/p from AGS to RHIC I. Bearden (BRAHMS) Becattini caluclation using statistical model: T=170, gs=1 (weak dependency) vary mB/T  K+/K- andp/p K- /K+=(p/p)1/4 is a empirical fit to the data points K-/K+ driven by ms ~ exp(2ms/T) p/p driven by mB ~ exp(-2mB/T) ms = ms (mB) since <S> = 0 QM2002 summary slide (Ullrich) BUT: Holds for y  0 (BRAHMS y=3)

  11. Radial flow M. Kaneta/N. Xu (STAR) <pT> prediction with Tth and <b> obtained from blastwave fit (green line) STAR <pT> prediction for Tch = 170 MeV and <b>=0 pp no rescattering, no flow no thermal equilibrium preliminary F. Wang

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

  13. STAR Elliptic Flow dN/d(f -YR ) = N0 (1 + 2V1cos (f-YR) + 2V2cos (2(f-YR)) + ... ) Particle asymmetry V2 midrapidity : |h| < 1.0 Normalized Multiplicity

  14. Preliminary STAR STAR Preliminary Centrality dependence @ RHIC. Note possible dependence on low pt cut 200 GeV: 0.2< pt < 2.0 130 GeV: 0.075< pt < 2.0 200 GeV: 0.150< pt < 2.0 4-part cumulants v2=0.05 200 GeV: Preliminary - Consistent results - At 200 GeV better pronounced decrease of v2 for the most peripheral collisions. QM2002 summary slide (Voloshin)

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

  16. Growth of Limiting Fragmentation Region UA5, Z.Phys.C33, 1 (1986) p + p inel. dNch/dh ¢/<Npart> 6% central dN/dh¢ PHOBOS Au+Au 19.6 GeV is preliminary Systematic errors not shown

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

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

  19. NEW: Rapidity dependence of ratios at RHIC QM2002 summary slide (Ullrich) 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

  20. Boost-Invariance at RHIC ? p- Thomas Ullrich, QM2002 •  Boost invariance only achieved in small region |y|<0.5

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

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

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

  24. The 4 experiments Thomas Peitzmann, QM2002

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

  26. near-side correlation of charged tracks (STAR) trigger particle pT = 4-6 GeV/c Df distribution for pT > 2 GeV/c signature of jets also seen in g (p0) triggered events (PHENIX) trigger particle pT > 2.5 GeV/c Df distribution for pT = 2-4 GeV/c Jet Evidence in Azimuthal Correlations at RHIC QM2002 summary slide (Peitzmann) M. Chiu, PHENIX Parallel Saturday

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

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

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

  30. v2 impact parameter (fm) High pT v2 reaches geometric surface limit QM2002 (Voloshin) QM2002 (Filimonov, STAR) E. Shuryak, nucl-th/0112042

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

  32. kT dependence of Rout/Rside A. Enikizono QM2002 C.M. Kuo, QM2002 poster (PHOBOS) 200 GeV: @0.25 GeV/c

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

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

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

  36. Our state is extreme • Hot dense state • Freezeout temperature near theoretical transition • High Energy Density • Very black source. • v2 ~pT and ~ maximum allowed from surface • HBT Ro/Rs • Approximate Npart scaling of high pT particles • Explosive source. • Radial flow at roughly the speed of sound • HBT Ro/Rs • (Unlike 2-particle correlations) • Alternatively (or additionally): • Magic near-instantaneous freezeout • Blast wave or Humanic model • Puzzles left at high pT

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

  38. eBj~ 25 GeV/fm3 eBj~ 5 GeV/fm3 Lattice ec Energy Density Estimate (Bj) PRL 87 (2001) 052301 formation time: 0.2 - 1 fm

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