Tübingen 2003 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 20: Physik mit schweren Ionen II
HK 20.2: Gruppenbericht
Dienstag, 18. März 2003, 16:00–16:30, E
Mott Effect and J/ψ Dissociation at the Quark-Hadron Phase Transition — •G. Burau1, D. Blaschke1,2, Yu. Kalinovsky3, and T. Barnes4 — 1Department of Physics, University of Rostock, D-18051 Rostock, Germany — 2Bogoliubov Laboratory for Theoretical Physics, JINR Dubna, 141980 Dubna, Russia — 3Laboratory for Information Technologies, JINR Dubna, 141980 Dubna, Russia — 4Oak Ridge National Laboratory, Oak Ridge, TN 37831-6373, USA
We investigate the in-medium modification of pseudoscalar and vector mesons in a QCD motivated chiral quark model by solving the Dyson-Schwinger equations for quarks and mesons at finite temperature for a wide mass range of meson masses, from light (π, ρ) to open-charm (D, D*) states. At the chiral / deconfinement phase transition, the quark-antiquark bound states enter the continuum of unbound states and become broad resonances (hadronic Mott effect). We calculate the in-medium cross sections for charmonium dissociation due to collisions with light hadrons in a chiral Lagrangian approach, and show that the D and D* meson spectral broadening lowers the threshold for charmonium dissociation by π and ρ mesons. This leads to a step-like enhancement in the reaction rate. We suggest that this mechanism for enhanced charmonium dissociation may be the physical mechanism underlying the anomalous J/ψ suppression observed by NA50.