Anomalous kinetics of hard charged particles: Dynamical renormalization group resummation - art. no. 105019

We study the kinetics of the distribution function for charged particles of hard momentum in scalar QED. The goal is to understand the effects of infr ared divergences associated with the exchange of quasistatic magnetic photo ns in the relaxation of the distribution function. We begin by obtaining a kinetic transport equation for the distribution function for hard charged s calars in a perturbative expansion that includes hard thermal loop resummat ion. Solving this transport equation, the infrared divergences arising from absorption and emission of soft quasi-static magnetic photons are manifest in logarithmic secular terms. We then implement the dynamical renormalizat ion group resummation of these secular terms in the relaxation time approxi mation. The distribution function (in the linearized regime) is found to ap proach equilibrium as delta n(k)(t) = delta n(k)(t(0))e(-2 alpha T(t-t0)ln[ (t-t0)<(mu)over bar>]), with <(mu)over bar>approximate to omega(p) the plas ma frequency and alpha = e(2)/4 pi. This anomalous relaxation is recognized to be the square of the relaxation of the single particle propagator, prov iding a generalization of the usual relation between the damping and the in teraction rate. The renormalization group approach to kinetics reveals clea rly the time scale t(rel)approximate to(alpha T ln[1/alpha])(-1) arising fr om infrared physics and hinges upon the separation of scales t(rel)much gre ater than omega(p)(-1). [S0556-2821(99)04510-5].