Gluon fusion contribution to W+W- + jet production

TL;DR

This paper computes the gluon fusion contribution to W+W- plus jet production at the LHC, showing it enhances background estimates for Higgs searches and providing a public code for NLO QCD corrections.

Contribution

It presents the first detailed calculation of the gg -> W+W- g process, including a public code for NLO QCD corrections, relevant for Higgs boson searches at the LHC.

Findings

Gluon fusion increases W+W-+jet background by about 10% under ATLAS cuts.

The process is finite and gauge-invariant, allowing separate evaluation from NNLO corrections.

The study provides a public code integrated with MCFM for practical computations.

Abstract

We describe the computation of the $gg \to W^+W^-g$ process that contributes to the production of two $W$-bosons and a jet at the CERN Large Hadron Collider (LHC). While formally of next-to-next-to-leading order (NNLO) in QCD, this process can be evaluated separately from the bulk of NNLO QCD corrections because it is finite and gauge-invariant. It is also enhanced by the large gluon flux and by selection cuts employed in the Higgs boson searches in the decay channel $ H \to W^+W^-$, as was first pointed out by Binoth {\it et al.} in the context of $gg \to W^+W^-$ production. For cuts employed by the ATLAS collaboration, we find that the gluon fusion contribution to $pp \to W^+W^-j$ enhances the background by about ten percent and can lead to moderate distortions of kinematic distributions which are instrumental for the ongoing Higgs boson searches at the LHC. We also release a public code to compute the NLO QCD corrections to this process, in the form of an add-on to the package {\tt MCFM}.