Three-loop helicity amplitudes for photon+jet production

TL;DR

This paper computes three-loop helicity amplitudes for photon+jet production in QCD, providing precise theoretical predictions crucial for LHC experiments, using an improved tensor projection method to simplify calculations.

Contribution

It introduces a novel variation of the tensor projection method in the 't Hooft-Veltman scheme for three-loop calculations, avoiding unphysical polarization contributions and yielding compact analytic results.

Findings

Analytic three-loop helicity amplitudes expressed in harmonic polylogarithms.

Enhanced computational efficiency by avoiding unphysical polarization contributions.

Provides precise theoretical tools for photon+jet processes at the LHC.

Abstract

We present three-loop helicity amplitudes for the production of a single photon in association with one jet in Quantum Chromodynamics, a final state which provides a standard candle of the Standard Model at the Large Hadron Collider. We employ a recently-proposed variation of the so-called tensor projection method in the 't Hooft-Veltman scheme (tHV) which avoids the computation of contributions due to unphysical (-2$\epsilon$)-dimensional polarisations of the external states. We obtain compact analytic results expressed in terms of harmonic polylogarithms.