Isolated photon and photon+jet production at NNLO QCD accuracy and the ratio $R_{13/8}^\gamma$

TL;DR

This paper presents a new NNLO QCD calculation of the ratio of inclusive isolated photon cross sections at 8 TeV and 13 TeV, providing precise theoretical predictions for experimental measurements.

Contribution

It introduces a novel NNLO QCD computation of the photon ratio $R_{13/8}^ ext{\gamma}$ and discusses different photon isolation methods in fixed-order calculations.

Findings

The NNLO calculation improves theoretical accuracy for photon production ratios.

Comparison with ATLAS data shows good agreement within uncertainties.

Different isolation approaches impact the precision of theoretical predictions.

Abstract

We discuss different approaches to photon isolation in fixed-order calculations and present a new next-to-next-to-leading order (NNLO) QCD calculation of $R_{13/8}^\gamma$, the ratio of the inclusive isolated photon cross section at 8 TeV and 13 TeV, differential in the photon transverse momentum, which was recently measured by the ATLAS collaboration.