Collision integral for multigluon production in a scalar quark and gluon model

Abstract

A model of scalar gluons and scalar quarks that successfully gives a ln s behavior in high energy qq scattering and which contains a three gluon vertex is used to derive transport equations for the quarks and gluons. Quasiparticle and semiclassical approximations are utilized. In particular, the collision integral is studied. At first the terms are organized according to the number of gluon exchange interactions, and it is shown explicitly that the occurrence of all two body differential scattering cross sections in the Boltzmann equation requires an evaluation of all terms to this order. One obtains qg-> qg, q bar q->gg, qq->qq, and q bar q -> q bar q. An additional ordering according to the inverse number of colors reveals that the quark loop diagrams are suppressed, and diagrams that lead to gluon production or scattering dominate. The self energy with three gluons exchanged is then examined. From this, it is evident that initial as well as final state interactions enter into a generalized collision integral. The generalized Boltzmann-like equation involving n gluon exchange for quark transport is given.