NNLO Photon Production with Realistic Photon Isolation

TL;DR

This paper provides next-to-next-to-leading order (NNLO) theoretical predictions for isolated photon production at hadron colliders, incorporating realistic photon isolation criteria and both direct and fragmentation contributions, to improve comparison with experimental data.

Contribution

It introduces NNLO calculations for photon-plus-jet cross sections with realistic isolation, including fragmentation effects and uncertainty estimates from fragmentation functions.

Findings

NNLO predictions match experimental isolation criteria.

Comparison of two fragmentation functions estimates fragmentation uncertainty.

Enhanced accuracy in photon production cross section predictions.

Abstract

Isolated photon production at hadron colliders proceeds via direct production and fragmentation processes. Theory predictions for the isolated photon and photon-plus-jet cross section often impose idealised photon isolation criteria, eliminating the fragmentation contribution and introducing a systematic uncertainty in the comparison to data. We present NNLO predictions for the photon-plus-jet cross section with the experimental isolation including both, direct and fragmentation contributions. Predictions with two different parton-to-photon fragmentation functions are compared, allowing for an estimation of the uncertainty stemming from the only loosely constrained photon fragmentation functions.