Three-loop helicity amplitudes for diphoton production in gluon fusion

TL;DR

This paper computes the three-loop helicity amplitudes for gluon fusion into diphotons in massless QCD, providing essential components for next-to-next-to-leading order corrections in particle physics.

Contribution

It introduces a novel method within the 't Hooft-Veltman scheme to efficiently calculate compact three-loop helicity amplitudes for diphoton production.

Findings

Analytic three-loop helicity amplitudes obtained

Results are compact and numerically efficient

Completes the set of ingredients for NNLO QCD corrections

Abstract

We present a calculation of the helicity amplitudes for the process $gg\to\gamma\gamma$ in three-loop massless QCD. We employ a recently proposed method to calculate scattering amplitudes in the 't Hooft-Veltman scheme that reduces the amount of spurious non-physical information needed at intermediate stages of the computation. Our analytic results for the three-loop helicity amplitudes are remarkably compact, and can be efficiently evaluated numerically. This calculation provides the last missing building block for the computation of NNLO QCD corrections to diphoton production in gluon fusion.