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Quark Matter, 2002, Nantes Correlations and Fluctuations Summary

Summary of recent research on HBT measurements in high-energy nuclear collisions, covering pt fluctuations, multiplicity correlations, isospin/strangeness phenomena, and more. Scott Pratt from Michigan State University reviews recent findings and discusses the HBT puzzle, potential solutions, and future research directions.

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Quark Matter, 2002, Nantes Correlations and Fluctuations Summary

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  1. Quark Matter, 2002, NantesCorrelations and Fluctuations Summary Scott Pratt, Michigan State University • New HBT measurements • The HBT puzzle • pt fluctuations • Multiplicity correlations • Isospin/Strangeness fluctuations • Charge fluctuations and balance functions Scott Pratt Michigan State University

  2. HBT: pp AGS->SPS->RHIC: Rbeam:increases smoothly Rside: falls then rises Rout: changes little Scott Pratt Michigan State University

  3. pp HBT: Consensus at RHIC STAR ~ PHENIX ~ PHOBOS PHOBOS  Rout Rside Rlong - - 0.540.02 5.80.2 5.10.4 6.80.3 ++ 0.570.03 5.80.2 4.90.4 7.30.3 0.85 < Rout/Rside < 1.15 Scott Pratt Michigan State University

  4. HBT vs. Reaction Plane STAR • Out-of-plane extended • Opposite of RQMD • Rapid dissolution? Scott Pratt Michigan State University

  5. pp HBT: 3-Pion HBT • Chaoticity from STAR ~ 1 • Robustness is an issue Scott Pratt Michigan State University

  6. pp HBT: Breakup Density • Always model dependent • Varies from SPS to RHIC pions protons D. Adamova et al Also, see talk of B. Tomasik Scott Pratt Michigan State University

  7. High phase space densityLow entropyHydro: fits spectra / underpredicts R thereforeInitial state has less entropy than assumed in hydro pp HBT: Phase Space Density <f> pt Scott Pratt Michigan State University

  8. pp HBT: Entropy ÖSNN = 130 GeV Peripheral S/N Landau S/N for Bose Gas STAR Preliminary Central John G. Cramer Scott Pratt Michigan State University

  9. pp HBT: Entropy Low entropy suggests coherence in initial state colored-glass condensate? gluonic super-radiance? Scott Pratt Michigan State University

  10. KK HBT: NA49 PHENIX Scott Pratt Michigan State University

  11. KK and pp HBT: • Rp < RK < Rp M. Heffner, PHENIX Scott Pratt Michigan State University

  12. Correlations: New Species • L-p tests strangeness dynamics • Ks-Ks No Coulomb • LL Infer interaction Lp Correlation LL HBT NA49 Ks-Ks HBT STAR, preliminary Scott Pratt Michigan State University

  13. WA98: gg HBT • Measures Direct g!! • l ~ 1.005 requires10% direct g • Rinv ~ 6 fm C(Qinv) Qinv Scott Pratt Michigan State University

  14. WA98: gg HBT • Direct g spectra: Scott Pratt Michigan State University

  15. Non-Identical Particle Correlations Compare q1,out - q2,out >0 vs q1,out - q2,out <0 p ahead of K, K ahead of p fit by blast wave: T=110, <v>=0.5c hadronic models: K ahead of p Scott Pratt Michigan State University

  16. (F. Retiere, STAR) Out ratio • Non-Identical Particle • Correlations • Consistent with blast wave • pK would provide sensitive test NA49 Side ratio Long ratio Scott Pratt Michigan State University

  17. HBT PUZZLE Small Rout implies small Dt P.Kolb Small Rbeam implies small breakup t, ~10 fm/c Large Rside implies large R Scott Pratt Michigan State University

  18. HBT PUZZLE(S) 1. Why does the blast wave fit? (with Dt ~ 0) Where is the emission from the surface? (as in Hydro+Cascade) 2. Why does the matter fall fall apart so quickly?t ~ 10 fm/c, R ~ 13 fm, vmax ~ 0.75 Scott Pratt Michigan State University

  19. *presented here • Theory Investigations: • Hydro+Hadron Cascade tried multiple times(Teaney, *Soff, Bass & Dumitru, *Kolb, *Huovinen, *Hirano…) • Accounting for experimental resolution & Coulomb(*CERES, *Heffner, Brown, S.P.,STAR) • Viscous effects (*Teaney, *Heinz, S.P.) • Varying Chemical Rates and cross-sections(*Soff, *Hirano & Tetsufumi) • Non-Gaussian distortions(Brown, Kolb, Heinz, SBD) RESULT: Factor of 2 discrepancy reduced to 30% discrepancy In both short t puzzle and Rout/Rside puzzle Scott Pratt Michigan State University

  20. Possible Solutions to the HBT Puzzle • Anomalously stiff EOSWould cs=c be sufficient? • Phase boundary retards transportReduces emissivity (S. Padula)Implies super-cooling (T. Csorgo) • Is something wrong with the HBT dogma? Scott Pratt Michigan State University

  21. HBT: To-do List • Experiment: • Make Coulomb standard (See poster of M. Heffner) • Finish Kaon systematics • HBT as function of centrality (E735 from FNAL, pp) • Theory: • Solve the HBT puzzle Scott Pratt Michigan State University

  22. pt fluctuations • bigger acceptance  larger Fpt • ptcorrelations span largeDy and Df • Beware of the mundane. NA49 preliminary PHENIX Preliminary STAR Scott Pratt Michigan State University

  23. Multiplicity Fluctuations: Wavelet Analysis • Evidence for jet quenching STAR, HIJING,HIJING w/o JETS M.Kopytine multiplicity Scott Pratt Michigan State University

  24. Isospin Fluctuations • Theory: • Consider baryonic/strange degrees of freedom (Gavin, Wong) • Experiment: • First measurement of Nch/Ng • fluctuations in HI collisions • Fluctuations are small (WA98) Scott Pratt Michigan State University

  25. Charge fluctuations and balance functions • (N+-N-)2 driven by charge conservation Correlation functions Charge Fluctuations NA49 preliminary STAR preliminary Scott Pratt Michigan State University

  26. Charge fluctuations and balance functions • Measure separationof balancing charges • Can signal delayedhadronization Dh Scott Pratt Michigan State University

  27. Charge fluctuations and balance functions Balance Function Width • Separation decreases with centrality • Requires delayed production of charge (delayed hadronization) • Suggests creation of gluon-rich matter Scott Pratt Michigan State University

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