Evolution of charm-meson ratios in an expanding hadron gas

Abstract

We study the time evolution of the numbers of charm mesons after the kinetic freeze-out of the hadron gas produced by a central heavy-ion collision. The πD∗→πD∗ reaction rates have t-channel singularities that give contributions inversely proportional to the thermal width of the D. The ratio of the D0 and D+ production rates can differ significantly from those predicted using the measured D∗ branching fractions.