DISCRETE QCD, A NEW APPROXIMATION FOR QCD CASCADES

We consider a new approximation scheme to the perturbative QCD cascade s, discrete QCD, corresponding to an expansion in the phase space dens ity of the emitted partons. It turns out that this density in phase sp ace is very low and the reason can be traced to the physics behind the running coupling constant. The whole scheme only contains a single pa rameter, viz. the scale in the running coupling constant and is conseq uently strongly predictive. We show how to obtain analytical formulas for the multiplicity and the phase space distributions and compare to the results of the conventional cascade models (JETSET, ARIADNE and KE RWIG) as well as earlier analytical approximation schemes.