Production of three isolated photons in the high-energy factorization approach

We study large- p_T pT three-photon production at the LHC center-of-mass energy \sqrt{s}=8 display="inline">s=8 TeV. use LO approximation of parton Reggeization approach consistently merged with real NLO corrections. For numerical calculations parton-level generator KaTie and modified KMR-type unintegrated distribution functions. find good agreement between our predictions data same accuracy as in NNLO based on collinear model QCD. At higher energies ( \sqrt{s}=13 display="inline">s=13 27 TeV) predicts larger cross sections, up to \sim 10 display="inline">∼10 % 20 display="inline">∼20 %, respectively.