A kT-dependent sea-quark density for the CASCADE Monte Carlo event generator

Abstract

Parton-shower event generators that go beyond the collinear-ordering approximation at small x have so far included only gluon and valence quark channels at transverse momentum dependent level. We describe results of recent work to include effects of the sea-quark distribution with explicit dependence on the transverse quark-momentum.This sea-quark density is then applied to the description of forward Z -production. The qq*->Z matrix element (with one off-shell quark) is calculated in an explicit gauge invariant way, making use of high energy factorization. The kT-factorized result has been implemented into the CCFM Monte-Carlo CASCADE and a numerical comparison with the qg*->Zq matrix element has been carried out.