Quantum field kinetics of QCD: Quark-gluon transport theory for light-cone-dominated processes

A quantum kinetic formalism is developed to study the dynamical interplay ofquantum and statistical-kinetic properties of non-equilibrium multi-partonsystems produced in high-energy QCD processes. The approach provides the meansto follow the quantum dynamics in both space-time and energy-momentum, startingfrom an arbitrary initial configuration of high-momentum quarks and gluons.Using a generalized functional integral representation and adopting the`closed-time-path' Green function techniques, a self-consistent set ofequations of motions is obtained: a Ginzburg-Landau equation for a possiblecolor background field, and Dyson-Schwinger equations for the 2-point functionsof the gluon and quark fields. By exploiting the `two-scale nature' oflight-cone dominated QCD processes, i.e. the separation between the quantumscale that specifies the range of short-distance quantum fluctuations, and thekinetic scale that characterizes the range of statistical binary inter-actions, the quantum-field equations of motion are converted into a correspon-ding set of `renormalization equations' and `transport equations'. The formerdescribe renormalization and dissipation effects through the evolution of thespectral density of individual, dressed partons, whereas the latter determinethe statistical occurrence of scattering processes among these dressed partons.The renormalization equations and the transport equations are coupled, andhence must be solved self-consistently. This amounts to evolving themulti-parton system, from a specified initial configuration, in time and full7-dimensional phase-space. This description provides a proba- bilisticinterpretation and is therefore of important practical value for the solutionof the dynamical equations of motion, e.g. by Monte Carlo simulation.Comment: 70 pages, latex, 12 figures as uu-encoded postscript fil