NNLOPS accurate predictions for $W^+W^-$ production

TL;DR

This paper introduces NNLOPS accurate predictions for $W^+W^-$ production in hadron collisions, including all relevant diagrams, spin correlations, and off-shell effects, achieving full NNLOPS accuracy for a complex 2→4 process.

Contribution

The work presents the first full NNLOPS accuracy for a $2\to 4$ process, enhancing precision in $W^+W^-$ production predictions and including detailed effects like spin correlations and off-shell contributions.

Findings

Good agreement with ATLAS and CMS measurements.

Significant impact of NNLO corrections on differential distributions.

Defined a charge asymmetry sensitive to $W$ polarizations.

Abstract

We present novel predictions for the production of $W^+W^-$ pairs in hadron collisions that are next-to-next-to-leading order accurate and consistently matched to a parton shower (NNLOPS). All diagrams that lead to the process $pp\to e^- \bar \nu_e\;\mu^+\nu_\mu+X$ are taken into account, thereby including spin correlations and off-shell effects. For the first time full NNLOPS accuracy is achieved for a $2\to 4$ process. We find good agreement, at the 1$\sigma$ level, with the $W^+W^-$ rates measured by ATLAS and CMS. The importance of NNLOPS predictions is evident from differential distributions sensitive to soft-gluon effects and from the large impact ($10$% and more) of including next-to-next-to-leading order corrections on top of MiNLO. We define a charge asymmetry for the $W$ bosons and the leptons in $W^+W^-$ production at the LHC, which is sensitive to the $W$ polarizations and hence can be used as a probe of new physics.