Predictions for the isolated prompt photon production at the LHC at $ \sqrt s= $13 TeV

Abstract

The prompt photon production in hadronic collisions has a long history of providing information on the substructure of hadrons and testing the perturbative techniques of QCD. Some valuable information about the parton densities in the nucleon and nuclei, especially of the gluon, can also be achieved by analysing the measurements of the prompt photon production cross section whether inclusively or in association with heavy quarks or jets. In this work, we present predictions for the inclusive isolated prompt photon production in $ pp $ collisions at center-of-mass energy of 13 TeV using various modern PDF sets. The calculations are presented both as a function of photon transverse energy $ E_\textrm{T}^\gamma $ and pseudorapidity $ \eta^\gamma $ for the ATLAS kinematic coverage. We also study in detail the theoretical uncertainty in the cross sections due to the variation of the renormalization, factorization and fragmentation scales. Moreover, we introduce and calculate the ratios of photon momenta for different rapidity regions and study the impact of various input PDFs on such quantity.