Energy Loss Versus Energy Gain of Heavy Quarks in a Hot Medium

We study the energy loss and the energy gain of heavy quarks in a hot thermal medium, aiming to mimic the initial stage of the high energy nuclear collisions. The processes we are interested in include the energy change due to the polarization and to the interaction with the thermal fluctuations of the medium. The dynamics of the heavy quarks with the medium is described by the Wong equations, that allow for the inclusion of both the backreaction on the heavy quarks due to the polarization of the medium, and of the interaction with the thermal fluctuations of the gluon field. Both the momentum as well as the temperature dependence of the energy loss and gain of charm and beauty are studied. We find that heavy quark energy gain dominate the energy loss at high-temperature domain achievable at the early stage of the high energy collisions. This finding supports the recently observed heavy quarks results in glasma and will have a significant impact on heavy quark observables at RHIC and LHC energies.