Leading-Color Two-Loop QCD Corrections for Three-Photon Production at Hadron Colliders

TL;DR

This paper presents the first publicly available two-loop QCD corrections for three-photon production at hadron colliders, enabling precise theoretical predictions for this process.

Contribution

It introduces a novel calculation of two-loop helicity amplitudes for three-photon production using advanced numerical unitarity and analytic reconstruction methods.

Findings

Analytic expressions for two-loop amplitudes in QCD for three-photon production.

A public code for efficient evaluation of two-loop finite remainders.

Demonstration of numerical stability across the physical phase space.

Abstract

We compute the two-loop helicity amplitudes for the production of three photons at hadron colliders in QCD at leading-color. Using the two-loop numerical unitarity method coupled with analytic reconstruction techniques, we obtain the decomposition of the two-loop amplitudes in terms of master integrals in analytic form. These expressions are valid to all orders in the dimensional regulator. We use them to compute the two-loop finite remainders, which are given in a form that can be efficiently evaluated across the whole physical phase space. We further package these results in a public code which assembles the helicity-summed squared two-loop remainders, whose numerical stability across phase-space is demonstrated. This is the first time that a five-point two-loop process is publicly available for immediate phenomenological applications.