Prompt photon production with two jets in POWHEG

A bstract Prompt photon production is highly sensitive to the distribution of quarks and gluons in free protons and nuclei and an important baseline for phenomenological studies of the properties of the quark-gluon plasma. In this paper, we present a new calculation of the production of prompt photons in association with two jets at next-to-leading order in quantum chromodynamics matched to parton showers with the POWHEG method. This calculation extends our previous analysis of prompt photon production in association with one jet using POWHEG+PYTHIA. We investigate the role of the parton shower as an alternative description of the parton-to-photon fragmentation process and analyse correlations between the photon and the jets. In addition, we compare POWHEG+PYTHIA with POWHEG+HERWIG predictions, experimental ATLAS data for isolated photons, and a perturbative calculation at next-to-next-to-leading order. Both parton shower models bring the next-to-leading order prediction into good agreement with the experimental data and the next-to-next-to-leading order calculation.