Next-to-leading order QCD corrections to the top quark associated with $\gamma$ production via model-independent flavor-changing neutral-current couplings at hadron colliders

TL;DR

This paper calculates the complete next-to-leading order QCD corrections for top quark and photon production via flavor-changing neutral-current couplings at hadron colliders, showing significant cross section enhancements and reduced scale dependence.

Contribution

It provides the first comprehensive NLO QCD correction analysis for top quark FCNC processes involving photon and gluon couplings, including mixing effects.

Findings

NLO corrections increase cross sections by up to 80%.

Corrections significantly reduce scale dependence.

Results applicable to Tevatron and LHC energies.

Abstract

We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\gamma$ production induced by model-independent $tq\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the $tq\gamma$ and $tqg$ FCNC couplings for this process. Our results show that, for the $tq\gamma$ couplings, the NLO QCD corrections can enhance the total cross sections by about 50% and 40% at the Tevatron and LHC, respectively. Including the contributions from the $tq\gamma$, $tqg$ FCNC couplings and their mixing effects, the NLO QCD corrections can enhance the total cross sections by about 50% for the $tu\gamma$ and $tug$ FCNC couplings, and by about the 80% for the $tc\gamma$ and $tcg$ FCNC couplings at the LHC, respectively. Moreover, the NLO corrections reduce the dependence of the total cross section on the renormalization and factorization scale significantly. We also evaluate the NLO corrections for several important kinematic distributions.