Initial State Radiation in Simulations of Vector Boson Production at Hadron Colliders

The production of vector bosons at present and future hadron colliders will provide a crucial test for QCD and Standard Model physics. In this paper we improve parton shower simulations of Drell-Yan processes by implementing matrix-element corrections to the initial-state radiation. We apply our work to the HERWIG Monte Carlo event generator and compare our phenomenological results with the ones obtained using the previous version of HERWIG, with resummed calculations which we match to the exact first-order perturbative result, and with recent Tevatron data. We also make some predictions for jet events at the LHC.