Low-energy $e^+\,e^-\to\gamma\,\gamma$ at NNLO in QED

TL;DR

This paper provides a detailed NNLO QED calculation of electron-positron to two-photon scattering, enhancing precision tools for collider luminosity measurements at low energies.

Contribution

It introduces a fully differential NNLO QED computation for $e^+ e^- o \gamma \, \gamma$, integrated into the McMule framework, expanding its capabilities for $2 o 2$ processes.

Findings

Enables precise luminosity measurements at low-energy electron-positron colliders.

Completes NNLO calculations for key $2 o 2$ QED processes.

Provides a tool for improved theoretical predictions in collider physics.

Abstract

We present a fully differential computation of $e^+\,e^-\to\gamma\,\gamma$ at next-to-next-to-leading order in QED. The process has been implemented into McMule, completing its set of next-to-next-to-leading-order calculations for the most important $2 \to 2$ processes. The results allow for generic applications to electron-positron colliders with centre-of-mass energies up to a few GeV, particularly for luminosity measurements.