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Evidence for a Quark-Gluon Plasma at RHIC Part 2

Evidence for a Quark-Gluon Plasma at RHIC Part 2. John Harris Yale University. NATO ASI, Kemer, Turkey 2003. Creating and Probing the Quark-Gluon Quagmire at RHIC. On the “First Day” (at RHIC). Initial Observations : Large produced particle multiplicities

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Evidence for a Quark-Gluon Plasma at RHIC Part 2

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  1. Evidence for a Quark-Gluon Plasma at RHICPart 2 John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  2. John Harris Yale University NATO ASI, Kemer, Turkey 2003 Creating and Probing the Quark-Gluon Quagmire at RHIC John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  3. On the “First Day” (at RHIC) Initial Observations: Large produced particle multiplicities ed. - “less than expected! gluon-saturation?”  dnch/dh |h=0 = 670, Ntotal ~ 7500 > 15,000 q +q in final state, > 92% are produced quarks Au + Au CGC? PHENIX PHOBOS Large energy densities (dn/dh, dET/dh)  e  5 GeV/fm3 e  5 - 15 ecritical 30 - 100 x nuclear density Large collective flow ed. - “completely unexpected!”  Large early pressure gradients, energy & gluon densities  Hydrodynamic & requires quark-gluon equation of state! Quark flow & coalescence  constituent quark degrees of freedom! John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  4. 1 On the First Day at RHIC - Azimuthal Distributions STAR, PRL90 032301 (2003) b ≈ 10 fm b ≈ 6.5 fm b ≈ 4 fm peripheral collisions Top view Beams-eye view John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  5. 1 z p y x p Azimuthal anisotropy (momentum space) Early Pressure in System Elliptic Flow! Sufficient interactions early (< 1 fm/c) in system  to respond to early pressure!  before self-quench (insufficient interactions)! System is able to convert original spatial ellipticitymomentum anisotropy! Sensitive to early dynamics of system John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  6. 1 z y x curves = hydrodynamic flow zero viscosity, Tc = 165 MeV Elliptic Flow Saturates Hydrodynamic Limit • Azimuthal asymmetryof charged particles: dn/df ~ 1 + 2v2(pT) cos (2 f)+ ... • Mass dependence of v2 • Requires - • Early thermalization • (0.6 fm/c) • Ideal hydrodynamics • (zero viscosity) •  “nearly perfect fluid” • e ~ 25 GeV/fm3 ( >> ecritical ) • Quark-Gluon Equ. of State John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  7. If baryons and mesons formfrom independently flowing quarksthenquarks are deconfined for a brief moment (~ 10 -23 s), then hadronization! John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  8. Universality of Classical Strongly-Coupled Systems Transport in gases of strongly-coupled atoms RHIC fluid behaves like this – a strongly coupled fluid. Universality of classical strongly-coupled systems?  Atoms, sQGP, AdS/CFT……

  9. h/s (water) >10 h/s (limit) = 1/4p Ultra-low (Shear)Viscosity Fluids 4p h/s QGP Quantum lower viscosity bound: h/s > 1/4p (Kovtun, Son, Starinets) From strongly coupled N = 4 SUSY YM theory. 2-d Rel Hydro describes STAR v2 data withh/s  0.1 near lower bound! John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  10. Scientific American, November 2005 Ultra-low Viscosity Fluids “A test comes from RHIC ….. A preliminary analysis of these experiments indicates the collisions are creating a fluid with very low viscosity.” “Black holes have an extremely small shear viscosity – smaller than any known fluid… Strongly interacting quarks and gluons at high T should also have a very low viscosity.” John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  11. “The RHIC fluid may be theleast viscous non-superfluid ever seen” The American Institute of Physics announced the RHIC quark-gluon liquid as the top physics story of 2005! see http://www.aip.org/pnu/2005/ John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  12. It Flows - Is It Really Thermalized? “Chemical” equilibration (particle yields & ratios): Particles yields represent equilibrium abundances universal hadronization temperature Small net baryon density(K+/K-,B/B ratios) mB ~ 25 - 40 MeV Chemical Freezeout Conditions T = 177 MeV, mB = 29 MeV T ~ Tcritical (QCD) John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  13. At RHIC: T = 177 MeV T ~ Tcritical (QCD) QCD Phase Diagram John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  14. Particles are thermally distributed and flow collectively,at universal hadronization temperature T = 177 MeV! John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  15. leading particle hadrons hadrons leading particle Probing Hot QCD Matter with Hard-Scattered Probes John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  16. High Momentum Hadrons Suppressed - Photons Not Deviations from binary scaling of hard collisions: dev Photons Hadrons factor 4 – 5 suppression John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  17. Final State Suppression / Initial State Enhancement! • The hadron spectra at RHIC from p+p, Au+Au and d+Au collisions establish existence of early parton energy loss, a new final-state effect,from strongly interacting, dense QCD matter in central Au-Au collisions Au + Au Experiment d + Au Control Experiment Final Data Final Data John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  18. RHIC data sQGP QGP R. Baier Pion gas Cold nuclear matter pT = 4.5 – 10 GeV/c Much larger energy loss than expected from perturbation theory Energy Loss of Hard Scattered Parton Energy loss requires large dev (Dainese, Loizides, Paic, hep-ph/0406201) John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  19. Heavy Charm and Beauty Quarks Heavy quarks thought too massive to be attenuated by medium! Au + Au  non-photonic electrons Late Breaking News Single non-photonic electrons (from D and B mesons) → suppressed! Heavy quarks flow like light quarks! John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  20. Jet event in e+e-collision STAR Au+Au (jet?) event Hard Scattering (Jets) as a Probe of Dense Matter II STAR p + p  jet event Can we see jets in high energy Au+Au? John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  21. Hard Scattering: Two-Particle Azimuthal Correlations Technique: Azimuthal correlation function Trigger particle pT > 4 GeV/c Associate tracks 2 < pT < pT(trigger) STAR di-jets from p + p at 200 GeV John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  22. Hard Scattering: Two-Particle Azimuthal Correlations Technique: Azimuthal correlation function Trigger particle pT > 4 GeV/c Associate tracks 2 < pT < pT(trigger) Dh < 0.5 Dh > 0.5 STAR 130 GeV Au + Au, central trigger • short range  correlation: • jets + elliptic flow • long range  correlation: • elliptic flow John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  23. Relative Charge Dependence Strong dynamical charge correlations in jet fragmentation  “charge ordering” ||<0.5 - ||>0.5 (scaled) Au+Au ||<0.5 - ||>0.5 (scaled) 0<||<1.4 Au+Au p+p 0<||<1.4 Ref: PLB 407 (1997) 174. p+p pT > 4 GeV/c particle production mechanism same in central Au+Au & pp STAR Preliminary @ 200 GeV/c 0-10% most central Au+Au p+p minimum bias 4<pT(trig)<6 GeV/c 2<pT(assoc.)<pT(trig) Compare ++ and - - correlations to +- John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  24. Using p+p to Study Au+Au Jet Correlations Assume: high pT triggered Au+Au event is a superposition: high pT triggered p+p event + elliptic flow of AuAu event Central Au + Au Peripheral Au + Au disappears STAR 200 GeV/c peripheral & central Au+Au p+p minimum bias 4<pT(trig)<6 GeV/c 2<pT(assoc.)<pT(trig) • v2 from reaction plane analysis • A from fit in non-jet region (0.75 < || < 2.24) Away-side jet John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  25. no jet quenching! d + Au “di-jet” correlations similar to p + p Pedestal&flow subtracted Hammering the Nail in the Coffin Au + Au away-side correlation quenched! Quenching of Away-side “jet” is final state effect John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  26. Hard Scattering Conclusions x High Pt hadrons suppressed in central Au + Au enhanced in d + Au Back-to-back Jets Di-jets in p + p, d + Au (all centralities) Away-side jets quenched in central Au + Au  emission from surface  strongly interacting medium John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  27. Jet correlations in proton-proton reactions. Strong back-to-back peaks. Jet correlations in central Gold-Gold. Away side jet disappears for particles pT > 2 GeV Jet correlations in central Gold-Gold. Away side jet reappears in particles pT > 200 MeV Where Does the Energy Go? dev Color wakes? J. Ruppert & B. Müller Mach cone from sonic boom? H. Stoecker J. Casalderrey-Solana & E. Shuryak Cherenkov-like gluon radiation? I. Dremin A. Majumder, X.-N. Wang Azimuthal Angular Correlations Lost energy of away-side jet is redistributed to rather large angles! John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  28. Suppression Factor Charmonium Suppression - Deconfinement Late News Color screening of cc pair results in J/y (cc) suppression! J/y suppressed but less than expected? (more to do!) John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  29. d d d Au Au Au Au Au Au x ~ 10-3 x ~ 10-4 Experimental Evidence for Initial State Gluon Saturation Suppression of forward hadrons consistent with saturation of low-x gluons. Suppression Factor Centrality dependence & x dependence test CGC x ~ 10-3 x ~ 10-1 x ~ 10-2 John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  30. Summary Initial state gluon saturation (color glass condensate?) - forward rapidities  low-x d+Au is suppressed Ideal hydrodynamic flow → “perfect fluid” - Early thermalization & Quark-Gluon EOS x ~ 10-3 x ~ 10-4 Au+Au p+p Quark coalescence /flow  constituent quark degrees of freedom Away-side jet Trigger jet Equilibrium particle abundances – Universal hadronization T ~ Tcrit Rapid u, d, s equilibration near Tcrit Extreme initial densities – • e  5 GeV/fm3 • ~ 30 - 100 x nuclear density > 15,000 q+q in final state Jet energy loss – large gluon densities  strongly coupled QGP Strongly-coupled system of quarks and gluons (sQGP) formed at RHIC John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  31. Signatures & Properties of the QGP at RHIC • Large e > ec (T > Tc) system – QCD vacuum “melts” – NOT hadrons • Thermalized system of quarks and gluons – NOT just q & g scattering • Large elliptic & radial flow fluid flow (“perfect”!) • Heavy quark (charm) flow • Particle ratios fit by thermal model T = 177 MeV ~ Tc (lattice QCD) • System governed by quark & gluon Equation of State – NOT hadronic • Flow depends upon particle (constituent quark & gluon) masses • QGP EoS,, quark coalescence • Deconfined system of quarks and gluons – NOT hadrons • Flow already at quark level, charmonium suppression (tbd) • Weakly-interacting QGP (predicted by Lattice QCD) – NOT!!! • Strongly interacting quarks and gluons ….degrees of freedom (tbd) • Strongly-interacting QGP (NOT predicted by Lattice QCD) • Suppression of high pT hadrons, away-side jet quenched • Large opacity (energy loss) extreme gluon/energy densities •  strongly-interacting QGP (sQGP) John Harris (Yale) D. Allan Bromley Symposium, 8 - 9 December 2005

  32. Still to do! Shuryak, QM04 (flavor) Deconfined QGP? cc, bb suppression & melting sequence Chiral symmetry restoration? Thermalized heavy flavors? Open charm, beauty, multiply-strange baryon production & flow Establish properties of the sQGP medium Constituents? Transport properties (speed of sound, diffusion…) Flavor dependence of suppression & propagation Light vector mesons (mass and width modifications in medium) Direct Photon Radiation? New phenomena……. LHC & 40 x luminosity of RHIC & e-ion collider! Developments in theory (lattice, hydro, parton E-loss) “the adventure continues!” John Harris (Yale) Lake Louise Winter Institute, 18 – 23 February 2006

  33. Special Thanks for Contributions to This Presentation!! Mike Lisa Berndt Mueller Jamie Nagle Paul Sorenson John Harris (Yale) D. Allan Bromley Symposium, 8 - 9 December 2005

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