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News from PHENIX

News from PHENIX. David Morrison (BNL) for the PHENIX Collaboration. PHENIX data in hand. 130 GeV Au+Au: few x 10 6 minimum bias events recorded multiplicity, E T , charged hadrons, p 0 , correlations, fluctuations, electrons

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News from PHENIX

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  1. News from PHENIX David Morrison (BNL) for the PHENIX Collaboration

  2. PHENIX data in hand • 130 GeV Au+Au: few x 106 minimum bias events recorded • multiplicity, ET, charged hadrons, p0, correlations, fluctuations, electrons • 200 GeV Au+Au: 170x106 events sampled; 90x106 minimum bias, 14x106 rare event triggers • 200 GeV polarized p+p: 3.9x109 events sampled; 190x106 interaction triggers

  3. PHENIX from altitude of 15m

  4. Equilibrated system? Wide variety of particle ratios well fit in statistical model Hydro description of flow works well up to ~2 GeV/c Another example - fit single particle pT spectra in hydro inspired framework: Ref: E. Schnedermann, J. Sollfrank, and U. Heinz, Phys. Rev. C 48, 2462 (1993) Ref: S. Esumi, S. Chapman, H. van Hecke, and N. Xu, Phys. Rev. C 55, R2163 (1997)

  5. Experimental results PHENIX Preliminary PHENIX Preliminary PHENIX Preliminary Good simultaneous description of several pT spectra: T = 1224 MeV t = 0.72 0.01 2/dof = 30.0/40.0

  6. Energy density PHENIX for top 2% of distribution: dET/dh = 578+26-39 GeV e = 4.6 GeV/fm3 (t = 1 fm/c) cf. 405 GeV, 3.2 GeV/fm3 NA49 PRL 75, 3814, (1995) e = 15 GeV/fm3 (t = 0.3 fm/c)

  7. Hadrons at high pT in Au+Au yield per nucleon-nucleon collision in central A+A Define RAA: yield in “p+p” RAA as a function of pT highlights effects not present in fundamental nucleon-nucleon collisions: Cronin effect, possible “quenching” of high pT particles in deconfined matter.

  8. Experimental results PHENIX Cronin effect normalized to interpolated p+p results point-like suppression

  9. Closer comparison of p0 WA98 normalized to peripheral data PHENIX

  10. Charm via electrons Single electron spectrum – has contributions from Dalitz decays, conversions, etc. Account for those to attempt to deduce signal from heavy quark decay. PHENIX

  11. PYTHIA with TAB data are well described using PYTHIA cross-section multiplied by number of binary collisions obtained from nuclear thickness function, TAB (i.e., a Glauber model) – for all centralities. PHENIX

  12. In the spirit of the GRC ... ... and in accordance with all relevant PHENIX Collaboration by-laws (hereafter referred to as “the collaboration”), and recognizing that new physics results must be approved by an open meeting of said collaboration and that new results are being generated and vetted as I write these words and that in the context this conference any crazy interpretations of the data I may make are my fault alone ...

  13. If it walks like a duck ... equilibrated system high energy density light quark pT suppression ? point-like charm scaling ? ? ? fluctuations HBT radii etc. “The Big Duck”, Flanders, L.I., 40km from BNL

  14. Charge fluctuations PHENIX net charge: Q = N+- N- normalized variance: v(Q) = s(Q)/Nch expectation (cf. PRL 85, 2076 (2000)) that in QGP v(Q) ~ 0.2; for ordinary stochastic assignment of charges v(Q) ~ 1.0 PHENIX

  15. HBT: Rout,side vs kT PHENIX correlation parameters show different trend than expected in quantitative calculations: Rout=Rside Soff, Bass, Dumitru PRL 86, 3981 (2001) picture of space-time evolution of collision needs revisited

  16. Quantitative calculations consistent result: expect Rout/Rside > 1

  17. “Run2” and beyond • data shown so far are from “Run1” • PHENIX physics program is focused on rare events – which requires integrated luminosity • lepton pairs, very high pT, spin physics • Run2 has provided first taste of fairly large numbers of events

  18. p0 in p+p at Ös = 200 GeV 60x106 min. bias events p0 pT > 3.5 GeV/c

  19. high pTp0 full energy Au+Au 22x106 min. bias events p0 pT > 8 GeV/c

  20. So far ... and what’s next • evidence of largely equilibrated system with very high energy density • high pT light quarks less than point-like • charm production seems point-like • simplest explanation ... • much higher pT, p+p normalization, muons, electrons • polarized p+p program

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