NNLO QCD corrections to three-photon production at the LHC

TL;DR

This paper presents the first exact NNLO QCD calculations for three-photon production at the LHC, significantly improving theoretical predictions and reducing discrepancies with experimental data.

Contribution

It provides the first NNLO QCD calculation for a $2\to 3$ process, including the leading color approximation for the two-loop finite remainder.

Findings

NNLO corrections eliminate previous discrepancies with ATLAS data.

The missing two-loop corrections are estimated to be negligible.

The calculation enhances the precision of theoretical predictions for three-photon production.

Abstract

We compute the NNLO QCD corrections to three-photon production at the LHC. This is the first NNLO QCD calculation for a $2\to 3$ process. Our calculation is exact, except for the scale-independent part of the two-loop finite remainder which is included in the leading color approximation. We estimate the size of the missing two-loop corrections and find them to be phenomenologically negligible. We compare our predictions with available 8 TeV measurement from the ATLAS collaboration. We find that the inclusion of the NNLO corrections eliminates the existing significant discrepancy with respect to NLO QCD predictions, paving the way for precision phenomenology in this process.