A full Next to Leading Order study of direct photon pair production in hadronic collisions

TL;DR

This paper presents a comprehensive NLO QCD calculation for direct photon pair production in hadronic collisions, including fragmentation effects, with comparisons to experimental data and predictions relevant for Higgs searches at LHC.

Contribution

It provides a full next-to-leading order QCD calculation for photon pair production, implemented as a versatile event generator, including fragmentation contributions and detailed uncertainty analysis.

Findings

Good agreement with WA70 and D0 data

Predictions for Higgs background at LHC

Analysis of scale uncertainties and infrared sensitivities

Abstract

We discuss the production of photon pairs in hadronic collisions, from fixed target to LHC energies. The study which follows is based on a QCD calculation at full next-to-leading order accuracy, including single and double fragmentation contributions, and implemented in the form of a general purpose computer program of "partonic event generator" type. To illustrate the possibilities of this code, we present the comparison with observables measured by the WA70 and D0 collaborations, and some predictions for the irreducible background to the search of Higgs bosons at LHC in the channel $h \to \gamma \gamma$. We also discuss theoretical scale uncertainties for these predictions, and examine several infrared sensitive situations which deserve further study.