NNLO QCD corrections to $pp \to \gamma^* \gamma^*$ in the large $N_F$ limit

TL;DR

This paper calculates NNLO QCD corrections for off-shell photon pair production in proton collisions within a large quark flavor limit, advancing precision in theoretical predictions.

Contribution

It provides the first analytical computation of a gauge invariant subset of NNLO corrections for this process in the large $N_F$ limit.

Findings

Partial corrections are about 1-3% of the total cross-section.

Corrections vary with the photons' virtuality.

The work sets the stage for a complete NNLO calculation.

Abstract

We compute the NNLO QCD corrections for the hadroproduction of a pair of off-shell photons in the limit of a large number of quark flavors. We perform a reduction of the two-loop amplitude to master integrals and calculate the latter analytically as a Laurent series in the dimensional regulator using modern integration methods. Real radiation corrections are evaluated numerically with a direct subtraction of infrared limits which we cast in a simple factorized form. The results presented here constitute a gauge invariant part of the full NNLO corrections but are not necessarily dominant. We view this calculation as a step towards a complete computation. Our partial corrections to the total cross-section are about $1\%-3\%$ and vary with the virtuality of the two off-shell photons.