Next-to-leading order corrections to Wt production and decay

TL;DR

This paper provides a detailed next-to-leading order QCD calculation of Wt production and decay, including top quark and W boson decays, with implications for Higgs searches and background reduction at the LHC.

Contribution

It introduces a comprehensive NLO calculation for Wt production including decay effects and a novel diagram separation method using a b-jet veto.

Findings

QCD corrections are mild, up to 10% change in cross section at the LHC.

Radiative effects significantly reduce background events in Higgs searches.

NLO shapes of distributions can differ markedly from leading order predictions.

Abstract

We present the results of a next-to-leading order calculation of Wt production, including the decays of both the top quark and the W boson. The effects of radiation in the decay of the top quark are also included. The separation of diagrams which appear in the real corrections, into singly- and doubly-resonant contributions, is performed using a b-jet veto which is motivated by the use of the bottom quark distribution function. We find that, for a choice of scale which is suitable for this approach, the QCD corrections are very mild and only change the cross section by up to 10% at the LHC, depending on the severity of the b-jet veto. When further cuts are applied, applicable for a Higgs boson search in the H->WW channel, we find that the radiative effects greatly decrease the number of background events expected from this process. In addition, the shapes of relevant distributions can be significantly changed at next-to-leading order.