Next-to-Leading Order QCD Corrections to t

We present 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 the center-of-mass system energy of 7 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 the final top quark and the 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 pp →ttγ+X in the case that there exists an exotic top quark with an electric charge of −4e/3 at the 7 TeV LHC.