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We derive perturbatively the gap equations for a color-superconducting condensate with total spin J = 0 in dense QCD. At zero temperature, we confirm the results of Son for the dependence of the condensate on the coupling constant, and compute the prefactor to leading logarithmic accuracy. At nonzero temperature, we find that to leading order in weak coupling, the temperature dependence of the condensate is identical to that in BCSlike theories. The condensates for total spin J = 1 are classified; to leading logarithmic accuracy these condensates are of the same order as those of spin J = 0.

When there are many flavors of massless fermions, both three-dimensional electrodynamics, and a supersymmetric variant thereof, each spontaneously break chiral symmetry. For the latter, this occurs without breaking supersymmetry, and without a photino condensate.

We present a complete calculation of the gluon damping rate at zero momentum to leading order in the QCD coupling constant g. All terms of leading order in g are included by the resummation of an in6nite subset of higher-loop diagrams. At zero momentum, the damping rates for transverse gluons and plasmons are equal: the result is y=+0.264013g2T, where T is the temperature. The sign is positive, which implies that the quark-gluon plasma is perturbatively stable.Over the last decade, there has been much controversy concerning the damping rates for gluons in perturbative QCD at high temperature. ' Attention has focused on the plasmon, which is a collective, longitudinal mode of the gluon. Explicit one-loop calculations for the damping rate of the plasmon appeared to show that it is gauge dependent in both magnitude and sign. The calculations done to date, ' however, are incompletethere are higher-loop diagrams which contribute to the same order in the coupling constant g as the one-loop diagram. Following Ref.2, we developed in Ref. 3 a general and systematic method for resumming these higher-order effects into effective propagators and vertices. In Refs. 3 and 4 we showed that when the resummed perturbation expansion is used to include all terms of leading order in g, the gluon damping rate is independent of the choice of gauge, at least within Coulomb and covariant gauges. This is in accord with