JÕc production in relativistic heavy ion collisions from a multiphase transport model

Using a multiphase transport model, we study J/c production from interactions between charm and anticharm quarks in the initial parton phase and between D and D̄ mesons in the final hadron phase of relativistic heavy ion collisions at the relativistic heavy ion collider. Including also the inverse reactions of J/c absorption by gluons and light mesons, we find that the net number of J/c from the parton and hadron phases is smaller than that expected from the superposition of initial nucleon-nucleon collisions, contrary to the J/c enhancement predicted by the kinetic formation model. The production of J/c is further suppressed if one includes the color screening effect in the parton phase. We have also studied the dependence of J/c production on the charm quark mass and the effective charm meson mass.