Heavy-quark colorimetry of QCD matter

We consider propagation of heavy quarks in QCD matter. Because of large qua rk mass, the radiative quark energy loss appears to be qualitatively differ ent from that of light quarks at all energies of practical importance. Fini te quark mass effects lead to an in-medium enhancement of the heavy-to-ligh t D/pi ratio at moderately large (5-10 GeV) transverse momenta. For hot QCD matter a large enhancement is expected, whose magnitude and shape are expo nentially sensitive to the density of colour charges in the medium. (C) 200 1 Published by Elsevier Science B.V.