The next-to-leading order of the differential cross section of the subprocess of annihilation of quark-antiquark pair of prompt photon production in proton-proton collisions at NICA energies

Abstract

Next-to-the leading order of the differential cross-section of the subprocess of annihilation of quark-antiquark pair \(q\bar{q} \rightarrow gγ\) of prompt photon production in nonpolarized and longitudinally polarized proton-proton collisions at NICA energies has been investigated. Shown, that contribution of the next-to-leading order to the differential cross-section of annihilation of quark-antiquark pair \(q\bar{q} \rightarrow gγ\) is significant at the high energies of colliding protons and consist around 15\% of leading order calculation. The influence of longitudinal polarization of colliding protons on the contributions of the next-to-leading order is more significant than, on the contributions of the leading order and it is significant at high energies of colliding protons. PYTHIA 8.316 \textbf{+} POWHEG BOX Monte Carlo (MC) event generator has been used for numerically simulation of prompt photon production in annihilation of quark-antiquark pair in NLO approximation for determination of the dependences of cross section on the sum of energies of colliding protons \(\sqrt{s}\), transverse momentum \(p_{T}\), cosine of scattering angle \(Cos(θ)\), rapidity y of photon and \(x_{T}\). The NLO+PS simulation accurately reproduces the fundamental signatures of pQCD.