Charmonium in a hot medium: Melting vs. absorption

A charmonium produced in heavy ion collisions at RHIC and LHC propagates through a dense co-moving matter with a rather high relative momentum, 〈pT2〉=4-10 GeV2. In spite of Debye screening of the binding potential, the charmonium survives with a substantial probability, even if the c¯c potential is completely screened in the hot environment. In addition, the color-exchange interaction with the medium is another important source of charmonium suppression. Attenuation in a hot medium caused by both effects is evaluated by means of the path integral technique, which requires ability of boosting the binding potential to a moving reference frame. This problem is solved in the approximation of small intrinsic velocities of the charmed quarks.