Production of three isolated photons in the parton Reggeization approach at high energies

Abstract

We study a large-p T three-photon production in proton-proton collisions at the LHC. We use the leading order (LO) approximation of the parton Reggeization approach consistently merged with the next-to-leading order corrections originated from the emission of additional jet. For numerical calculations we use the parton-level generator KaTie and modified KMR-type unintegrated parton distribution functions which satisfy exact normalization conditions for arbitrary x. We compare our prediction with data from ATLAS collaboration at the center-of-mass energy √ s = 8 TeV. We find that the inclusion of the real next-to-leading-order corrections leads to a good agreement between our predictions and data with the same accuracy as for the next-to-next-to-leading calculations based on the collinear parton model of QCD. At higher energies ( √ s = 13 and 27 TeV) partonReggeization approach predicts larger cross sections, up to ∼ 15 % and ∼ 30 %, respectively.