  Theoretical studies of Higgs production via gluon fusion are frequently
carried out in the limit where the top quark mass is much larger than the Higgs
mass, an approximation which reduces the top quark loop to an effective vertex.
We present a numerical analysis of the error thus introduced by performing a
Monte Carlo calculation for gg->h in kT-factorisation, using the parton shower
generator CASCADE. We proceed to compare CASCADE to the collinear Monte Carlos
PYTHIA, MC@NLO and POWHEG. We study the dependence of parton radiation on the
resummation of high-energy corrections taken into account by kT-factorisation,
and its influence on predictions for the Higgs pT spectrum.
