Charmonium in a hot medium: melting vs absorption

TL;DR

This paper investigates how charmonium particles behave in hot dense media created in heavy ion collisions, considering effects like Debye screening and color-exchange interactions, and evaluates their survival probability using a path integral approach.

Contribution

It introduces a method to evaluate charmonium attenuation in hot media accounting for both screening and color interactions, with a novel boost technique for the potential.

Findings

Charmonium can survive despite complete screening of the potential.

Color-exchange interactions significantly contribute to suppression.

Survival probability depends on the medium's properties and charmonium momentum.

Abstract

A charmonium produced in heavy ion collisions at RHIC and LHC propagates through a dense co-moving matter with a rather high relative momentum, <p_T^2>=4-10GeV^2. In spite of Debye screening of the binding potential, the charmonium survives with a substantial probability, even if the c-cbar 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.