Quarkonium binding and entropic force

A Q anti Q bound state represents a balance between repulsive kinetic and attractive potential energy. In a hot quark-gluon plasma, the interaction potential experiences medium effects. Color screening modifies the attractive binding force between the quarks, while the increase of entropy with Q anti Q separation gives rise to a growing repulsion. We study the role of these phenomena for in-medium Q anti Q binding and dissociation. It is found that the relevant potential for Q anti Q binding is the free energy F; with increasing Q anti Q separation, further binding through the internal energy U is compensated by repulsive entropic effects. (orig.)