$W\gamma$ production at NNLO+PS accuracy in GENEVA

TL;DR

This paper introduces a high-precision event generator for $W\gamma$ production at NNLO+PS accuracy, combining resummation and fixed-order calculations within the GENEVA framework, validated against fixed-order results and LHC data.

Contribution

The paper develops and validates a novel NNLO+PS event generator for $W ext{ extbackslash}gamma$ production using GENEVA, integrating SCET resummation with fixed-order calculations.

Findings

Good agreement with ATLAS 7 TeV data.

Validated NNLO accuracy against fixed-order calculations.

Resummed 0-jettiness spectrum at NNLL' accuracy.

Abstract

We present an event generator for the process $pp\to \ell\nu_\ell\gamma$ at next-to-next-to-leading order (NNLO) in QCD and matched to the PYTHIA8 parton shower. The calculation makes use of the GENEVA framework, which combines a resummed calculation obtained via Soft-Collinear Effective Theory (SCET) with the fixed-order result. We validate the NNLO accuracy of our results by comparing predictions for inclusive quantities with an independent fixed-order calculation, and then present the resummed 0-jettiness spectrum at next-to-next-to-leading logarithmic (NNLL$'$) accuracy. Finally, we compare our predictions against data collected by the ATLAS experiment at the Large Hadron Collider during its 7 TeV run, finding good agreement.