1,903 research outputs found
Statistical J/psi production and open charm enhancement in Pb+Pb collisions at CERN SPS
Production of open and hidden charm hadrons in heavy ion collisions is
considered within the statistical coalescence model. Charmed quarks and
antiquarks are assumed to be created at the initial stage of the reaction and
their number is conserved during the evolution of the system. They are
distributed among open and hidden charm hadrons at the hadronization stage in
accordance with laws of statistical mechanics. The model is in excellent
agreement with the experimental data on J/psi production in lead-lead
collisions at CERN SPS and predicts strong enhancement of the open charm
multiplicity over the standard extrapolation from nucleon-nucleon to
nucleus-nucleus collisions. A possible mechanism of the charm enhancement is
proposed.Comment: Presented at 6th International Conference on Strange Quarks in
Matter, Frankfurt am Main, 2001. 4 pages, LaTeX, 1 PS-figur
Statistical hadronization of charmed quarks at SPS and RHIC
Production of open and hidden charm hadrons in heavy ion collisions is
considered within the statistical coalescence model. The charmed
quark-antiquark pairs are assumed to be created at the initial stage of the
reaction in hard parton collisions. The number of these pairs is conserved
during the evolution of the system. At the hadronization stage, the charmed
(anti)quarks are distributed among open and hidden charm hadrons in accordance
with the laws of statistical mechanics.
The model is in agreement with the experimental data on J/psi to Drell-Yan
ratio in Pb+Pb collisions at SPS. This agreement can be reached only if a
rather strong enhancement of the open charm production in central Pb+Pb
collisions is assumed. A possible mechanism of the charm enhancement is
discussed.
At the top RHIC energy, the model predicts an increase of J/psi to Drell-Yan
ratio in more central nucleus-nucleus collisions with respect to less central
ones.Comment: Presented at 16th International Conference "Quark Matter", Nantes
(France), July 18-24, 2002; 4 pages, LaTeX, 2 PS-figure
Evidence for psi' regeneration in heavy ion collisions
The study of hidden charm production is an important part of the heavy ion program. The standard approach to this problem [1] assumes that cÂŻc bound states are created only at the initial stage of the reaction and then partially destroyed at later stages due to interactions with the medium [2, 3, 4]
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