  The goal of this study is to find a prescription for defining parton
distributions (PDFs) which are most appropriate for use in those codes where
only LO matrix elements (MEs) are used, as in many Monte Carlo generators. We
describe a modification of LO PDFs, based on using alpha_S at NLO, a specific
prescription of the coupling in the QCD evolution, and violation of the
momentum sum rule. We compare results with the truth - the prediction using NLO
for both MEs and PDFs, and the standard LO prediction, finding that the
modified PDFs generally produce the best results.
