Diffusion of charmed quarks in the quark-gluon plasma

Abstract

We calculate the classical drag and diffusion coefficients for a charmed quark propagating in the quark-gluon plasma. Both coefficients turn out rather large, so that (1) a charmed quark created when the plasma is hot will be stopped before propagating 1 fm and (2) subsequent diffusion will be fast. The first effect should serve to increase the yield of J/ψ mesons in relativistic heavy-ion collisions, while the second should work in the opposite direction. In any case, the two effects should dominate the dynamics of a cc¯ pair.