CALCULATION OF THE QUARK DAMPING RATE IN HOT QCD

We present a complete calculation of the quark damping rate at zero momentum, to leading order in the QCD coupling constant g at a nonzero temperature T. All terms of leading order in g are included by the resummation of an infinite subset of higher-loop diagrams. At zero momentum the damping rates for the quark and the plasmino (a collective mode with opposite chirality and/or helicity) are equal: for three flavors of massless quarks, the result is gamma congruent-to 0.151g2T. We also examine the recent controversy over the gauge dependence of the quark damping rate, and show how it is resolved when dimensional regularization is used as an infrared regulator of mass singularities.