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Scott Pratt Michigan State University Have we seen the QGP at RHIC? Scott Pratt, Michigan State University MORE MEANINGFUL QUESTIONS: 1.Have we created MATTER ? 2.What are the defining properties of the new phase of matter (QGP) we expect to see at RHIC? 3.Is there experimental evidence for having created matter with these properties?
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Scott Pratt Michigan State University Have we created MATTER ? 1.Local kinetic equilibrium (even if not chemically equilibrated) 2.Large enough volume for bulk quantities to apply (otherwise we are studying reactions) Requirements for MATTER :
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Scott Pratt Michigan State University Have we created Matter ? Kinetic equilibrium: 1. Thermal features to spectra (exponential shape, -K-p systematics)
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Scott Pratt Michigan State University Have we created Matter ? System Size: 1. Elliptic Flow is large Approaching hydro limit -> low visosity -> short mean free path
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Scott Pratt Michigan State University Have we created Matter ? System Size: 2. Jets are quenched System is opaque to even high-energy partons!
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Scott Pratt Michigan State University Have we created Matter ? YES ! -- and at high energy density, (accounting for longitudinal work and motion, ~ 10 GeV/fm 3 )
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Scott Pratt Michigan State University Properties of the QGP 1.Quarks and Gluons are correct quasi-particles 2.Low pressure (compared to gas at same ) 3.Low T & high entropy (compared to gas at same ) 4.Chiral symmetry restored (shifted mass) 5.Opaque to jets 6.Large fluctuations (e.g. droplets)
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? 1.Balance function Most charge is created at hadronization, especially for gluon-rich medium If +/- pairs are more are created later, they are more correlated in rapidity Late hadronization = narrow B( y)
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? S.P., S.Cheng, S.Petriconi and M.Skoby, in prep. 1. Balance Function Width narrows with increasing centrality QUALITATIVELY consistent with expectations for QGP QUANTITATIVELY consistent with blast- wave with LOCAL charge charge conservation
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? S.P., S.Cheng, S.Petriconi and M.Skoby, in prep. Blast Wave Calc. Full canonical treatment Resonances included FSI included STAR acceptance and efficiency included T = 120, v = 0.7 Totally local NARROWEST POSSIBLE RESULT
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? 1.Balance function To do: Make K + /K - and pbar-p balance functions During hadronization, 1000 partons -> 1000 hadrons 350 gluons + 450 ud quarks + 200 s quarks -> 2000 ud quarks + 200 s quarks Expand analyses to Q inv, Q out, Q side, Q long Build the time-of-flight wall !
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? 2. Di-lepton measurements should dissolve Broad strength for M inv ~ 450 MeV To do: Build time-of-flight wall !
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? 3. Jet Quenching & J/Psi Gluon-rich medium should be opaque to jets Near T c, matter is strongly interacting To do: Pat yourselves on the back ! Gamma tagging Open charm Search low-pt data for jet remnants S.Pal and S.P., to appear in PLB
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Scott Pratt Michigan State University Are quarks/gluons correct quasi-particles? 4. Flow Gluon-rich medium should accelerate s Hadronic medium should be invisible To do: more statistics
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Scott Pratt Michigan State University Is the pressure low? 1. Radial/elliptic flow is large, v ,max ~ 0.7 From fitting , K, p spectra, J. Burward-Hoy, BNL Thermalfest 2001
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Scott Pratt Michigan State University Is the pressure low? Compared to STAR: R beam 80% too large R side 10% too large R out 40% too large Similar conclusions: P. Kolb, A.Dumitru, P. Huovinen and S. Bass D. Teaney, PhD thesis, EOS has Phase transition Hydro + RQMD STAR
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Scott Pratt Michigan State University Is the pressure low? NO !
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Scott Pratt Michigan State University Is the pressure low? To do: Analyze 3-d correlations for different species Angle between q and outwards axis S.P. and S.Petriconi, to appear in PLB
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Scott Pratt Michigan State University Is T low? (or high S ) 1.Lattice calculation give low T vs. (latent heat) 2. Low T implies high entropy
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Scott Pratt Michigan State University Is T low? (or high S ) 1.T 0 is not directly accessible (direct photons) 2.dS 0 /dy 0 due to shocks, viscosity, decoupling 3.Entropy can be extracted from experiment in a model-independent fashion (talk to John Cramer) dS /dy from HBT & spectra dS K /dy from HBT & spectra or from /K dS p /dy from d/p For other species, use spectra and guess about R HBT
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Scott Pratt Michigan State University Is T low? (or high S ) S.Pal and S.P., in preparation hydro Bjorken
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Scott Pratt Michigan State University Is T low? (or high S ) Conclusions: From hydro perspective, not enough entropy for QGP Adding viscosity might not help Using lower entropy phase, e.g. pion gas, helps Calc.s by T.Humanic, Z.Lin, D.Molnar, S.P. To do: Increase particle ID capabilities out to ~ 1.5 GeV Build the time-of-flight wall ! Measure direct photons
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Scott Pratt Michigan State University Is chiral symmetry restored? meson is perfectly designed, << fireball Difficult to distinguish mass shift/spread from dissolving To do: Build time-of-flight wall ! Talk to Zhangbu Xu
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Scott Pratt Michigan State University Is the matter opaque to jets? Suppression of high-pt jets PHENIX STAR Disappearance of away-side jets
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Scott Pratt Michigan State University Is the matter opaque to jets? YES! To do: tagging Search low pt for jet remnants (talk to Fuqiang Wang) S.Pal and S.P. to appear in PLB
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Scott Pratt Michigan State University Are fluctuations/ correlations large? Yes, but difficult to identify source jets initial proton overlap HBT-like resonances elliptic flow … To do: 6-D analysis of source of long-range correlations Identify species involved Build time-of-flight wall ! Pray for theoretical help
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Scott Pratt Michigan State University Summary 1.Quarks and Gluons are correct quasi-particles 2.Low pressure (compared to gas at same ) 3.Low T & high entropy (compared to gas at same ) 4.Chiral symmetry restored (shifted mass) 5.Opaque to jets 6.Large fluctuations (e.g. droplets) ? ? Build the time-of-flight wall ! (Balance function, dileptons, fluctuations, HBT…)
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