Next-to-leading order QCD corrections to $t\bar t\gamma$ production at the 7 TeV LHC

TL;DR

This paper provides detailed NLO QCD predictions for top-quark pair production with a photon at the 7 TeV LHC, including cross sections, distributions, and the effects of potential exotic top-quark charges.

Contribution

It offers the first complete NLO QCD calculations for $t\bar t\gamma$ production at 7 TeV LHC, including uncertainties and the impact of exotic top-quark charges.

Findings

NLO corrections significantly affect cross sections and distributions.

Quantitative $K$-factors for different photon transverse momentum cuts.

QCD corrections influence the interpretation of potential exotic top-quark charges.

Abstract

We present the theoretical predictions including the complete next-to-leading order (NLO) QCD corrections to the top-quark pair production in association with a photon at the LHC with center-of-mass system energy of $7 {\rm TeV}$. The uncertainties of the leading order (LO) and NLO QCD corrected cross sections due to the renormalization/factorization scale, and the distributions of the transverse momenta of final top-quark and photon are studied. Moreover, we provide the numerical results of the LO, NLO QCD corrected cross sections and the corresponding $K$-factors with different photon transverse momentum cuts. We also discuss the impact of QCD corrections to the \ppttga in case of there existing the exotic top-quark with an electric charge of $-4e/3$ at the $7 {\rm TeV}$ LHC.