WINHAC - the Monte Carlo event generator for single W-boson production in hadronic collisions

Abstract

We present the Monte Carlo event generator WINHAC for the charged-current Drell-Yan process, i.e. single W-boson production with leptonic decays in hadronic collisions. It features multiphoton radiationwithin the Yennie-Frautschi-Suura exclusive exponentiation scheme with O(alpha) electroweak corrections. For the initial-state QCD/QED parton shower and hadronisation it is interfaced directly to PYTHIA. It implements the options for proton-proton, proton-antipronton and any nucleus-nucleus collisions. Moreover, it includes the polarized W-boson production and the neutral current Drell-Yan process, both at the Born level. Generation of weighted as well as unweighted (weight=1) events is possible. WINHAC has been thoroughly tested numerically and cross-checked with independent Monte Carlo programs, such as HORACE and SANC; in the so-called tuned comparisons, an agreement at the sub-permil-level has been reached. It has also been used as a basic tool for developing and testing some new measurement methods of the Standard Model parameters at the LHC.