QCD corrections to associated production of $t\bar t\gamma$ at hadron colliders

TL;DR

This paper presents a detailed next-to-leading order QCD calculation for top-quark pair production with an associated photon at hadron colliders, improving theoretical predictions for cross sections and distributions.

Contribution

The paper provides the first complete NLO QCD corrections to $t\bar t\gamma$ production, including cross sections, distributions, and asymmetries at Tevatron and LHC.

Findings

NLO corrections significantly reduce scale dependence.

K-factor is approximately 0.977 at Tevatron and 1.524 at LHC.

Distributions and asymmetries are computed at NLO.

Abstract

We report on the next-to-leading order(NLO) QCD computation of top-quark pair production in association with a photon at the Fermilab Tevatron RUN II and CERN Large Hadron Collider(LHC). We describe the impact of the complete NLO QCD radiative corrections to this process, and provide the predictions of the leading order(LO) and NLO integrated cross sections, distributions of the transverse momenta of top-quark and photon for the LHC and Tevatron, and the LO and NLO forward-backward top-quark charge asymmetries for the Tevatron. We investigate the dependence of the LO and NLO cross sections on the renormalization/factorization scale, and find the scale dependence of the LO cross section is obviously improved by the NLO QCD corrections. The K-factor of the NLO QCD correction is $0.977(1.524)$ for the Tevatron(LHC).