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IN-MEDIUM FORMATION OF QUARKONIUM (“RECOMBINATION”) R. L. THEWS UNIVERSITY OF ARIZONA SQM2006 UCLA MARCH 26-31, 2006
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IN-MEDIUM FORMATION HIGH ENERGY EVOLUTION OF MATSUI-SATZ: R plasma screening < R quarkonium SUPPRESSION in a static medium, or KHARZEEV-SATZ: Ionization with deconfined gluons Charm pair diffuse away, will not recombine during deconfinement phase or at hadronization NEW SCENARIO AT COLLIDER ENERGIES
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Multiple ccbar pairs in high energy AA Collisions 10-15 from extrapolation of low energy 20 from PHENIX electrons 40 from STAR electrons and K CENTRAL VALUES AT RHIC: AND AT LHC: 100-200??
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PROBE REGION OF COLOR DECONFINEMENT WITH MULTIPLE PAIRS OF HEAVY QUARKS Avoids Matsui-Satz Condition Form Quarkonium directly in the Medium Formation and Suppression Competition Scenario supported by lattice calculations of quarkonium spectral functions (J/ y and h c )
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IF THE INCOHERENT RECOMBINATION OF HEAVY QUARKS DETERMINES FINAL HADRONIC ABUNDANCES:
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QUARKONIUM FORMATION MODELS IN REGION OF COLOR DECONFINEMENT STATISTICAL HADRONIZATION: P. Braun-Munzinger, J. Stachel, Phys. Lett B490 (2000) 196 [nucl-th/0007059]. KINETIC IN-MEDIUM FORMATION: R. L. Thews, M. Schroedter, J. Rafelski, Phys. Rev. C63 (2001) 054905 [hep-ph/0007323].
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IF THE INCOHERENT RECOMBINATION OF HEAVY QUARKS DETERMINES FINAL HADRONIC ABUNDANCES:IF THE INCOHERENT RECOMBINATION OF HEAVY QUARKS DETERMINES FINAL HADRONIC ABUNDANCES: IN-MEDIUM FORMATION R. L. Thews, M. Schroedter, J. Rafelski, Phys. Rev. C63 (2001) 054905 [hep-ph/0007323]. L. Grandchamp, R. Rapp, Phys. LettB52360 (2001) [hep-ph/0103124]. L. Grandchamp, R. Rapp, G. E. Brown Phys Rev Lett 92, 212301 (2004).
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Suppression of Initially Produced J/y
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Continuous In-Medium Formation followed by Partial Suppression
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COMPARISON WITH INITIAL PHENIX DATA AT RHIC 200 Rates very sensitive to quark momentum distribution Centrality signature varies with magnitude of N cc Initial indication for suppression below binary scaling Agreement within a region of model parameter space
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Kinetic Model Statistical Model predictions very sensitive to N cc and distribution Therm+Form
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+ Model predictions very sensitive to N cc and distribution
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R. L. Thews and M. L. Mangano Phys. Rev. C73, 014904 (2006) [nucl-th/0505055] 1.Generate sample of ccbar pairs from NLO pQCD (smear LO q t ) 2.Supplement with k t to simulate initial state and confinement effects 3.Integrate formation rate using these events to define particle distributions (no cquark-medium interaction) 4.Repeat with cquark thermal+flow distribution (maximal cquark-medium interaction) CAN Y AND P T SPECTRA PROVIDE SIGNATURES OF IN-MEDIUM FORMATION?
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All combinations of c and cbar contribute Total has expected (N ccbar ) 2 / V behavior Prefactor is integrated flux per ccbar pair
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P T distribution shows minimal variation with y interval
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p-p data “select” unbiased diagonal c-cbar pairs
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p-p data determine intrinsic k t
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Use dAu broadening to determine nuclear k t
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S. Gavin and M. Gyulassy, Phys. Lett. B214 (1988) Nuclear broadening from Initial state parton scattering, extract l 2 = 0.56 +/- 0.08 GeV 2 for Au-Au at RHIC, compare with 0.12 +/-.02 GeV 2 at fixed-target energy. Note: l and n are correlated within given nuclear geometry.
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Formation through “off-diagonal” pairs narrows rapidity distribution
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Formation through “off-diagonal” pairs narrows p t distribution
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Comparison with Thermal + Transverse Flow c-Quark Distributions K.A.Bugaev, M. Gazdzicki, M.I.Gorenstein, Phys.Lett.B544,127(2002) S.Batsouli, S.Kelly, M.Gyulassy, J.L.Nagle, Phys.Lett.B557,26 (2003)
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Comparison with coalescence model: V Greco, C. M. Ko, R. Rapp, Phys. Lett. B595:202 (2004)
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R AA (N coll ) points toward In-Medium Formation (AKA regeneration, coalescence, recombination) as the mechanism for J/y production in central Au-Au at RHIC. However, sequential suppression remains viable option. Must pin down many model parameters (N open charm ), system volume V(t) and temperature T(t), flow, etc. Normalized p T and y spectra alone can provide signatures of in-medium recombination processes The difference of pQCD vs thermal+flow quark pair distributions survives in the J/y spectra Variation of with system size and centrality provides characteristic signals of in-medium formation SUMMARY
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Initial PHENIX measurements of differ between rapidity intervals, not allowed if J/y reflects underlying ccbar pair distributions. Subject to large uncertainties, the in-medium scenario may be preferred. Initial PHENIX measurements of y spectra do not exhibit narrowing predicted by in-medium formation Thermal + flow charm quarks lead to extremely small, combination with initial production required J/y flow work in progress What about sQGP? Can we retain a scenario of binary interactions? Perhaps charm quarks will not even propagate in the medium.
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