Non-perturbative computation of gluon mini-jet production in nuclear collisions at very high energies

Abstract

At very high energies, in the infinite momentum frame and in light-cone gauge, a hard scale proportional to the high parton density arises in QCD. In an effective theory of QCD at small x, this scale is of order α s μ, where μ is simply related to the gluon density at higher rapidities. The ab initio real time evolution of small x modes in a nuclear collision can be described consistently in the classical effective theory and various features of interest can be studied non-perturbatively. In this paper, we discuss results from a real time SU(2) lattice computation of the production of gluon jets at very high energies. At very large transverse momenta, k t ⩾ μ, our results match the predictions from pQCD based mini-jet calculations. Novel non-perturbative behavior of the small x modes is seen at smaller momenta k t ∼ α s μ. Gauge invariant energy-energy correlators are used to estimate energy distributions evolving in proper time.