Higher-order corrections in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>t</mml:mi><mml:mover accent="true"><mml:mi>t</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mi>γ</mml:mi></mml:math> cross sections

Abstract

We study higher-order QCD corrections for the associated production of a top-antitop quark pair and a photon ($t\overline{t}\ensuremath{\gamma}$ production) in proton-proton collisions. We calculate the approximate next-to-next-to-leading order cross section, with second-order soft-gluon corrections added to the complete next-to-leading order result, including uncertainties from scale dependence and from parton distributions. We compare our results to recent measurements from the LHC, and find that the soft-gluon corrections provide improved agreement with the data. We also calculate differential distributions in top-quark transverse momentum and rapidity.

Topics & Concepts