Polarisation at NLO in WZ production at the LHC

TL;DR

This paper provides precise NLO theoretical predictions for polarisation observables in WZ production at the LHC, aiding the search for new physics through gauge boson spin measurements.

Contribution

It introduces fiducial polarisation observables for W and Z bosons and demonstrates the effectiveness of the double-pole approximation at NLO in electroweak corrections.

Findings

NLO predictions include QCD and electroweak corrections.

Double-pole approximation works well for WZ production.

Predictions support experimental measurements of gauge boson polarisation.

Abstract

The pair production of a $W$ and a $Z$ boson at the LHC is an important process to study the triple-gauge boson couplings as well as to probe new physics that could arise in the gauge sector. In particular the leptonic channel $p p \to W^\pm Z\to 3\ell +\nu + X$ is considered by ATLAS and CMS collaborations. Polarisation observables can help pinning down new physics and give information on the spin of the gauge bosons. Measuring them requires high statistics as well as precise theoretical predictions. We define in this contribution fiducial polarisation observables for the $W$ and $Z$ bosons and we present theoretical predictions in the Standard Model at next-to-leading order (NLO) including QCD as well as NLO electroweak corrections, the latter in the double-pole approximation. We also show that this approximation works remarkably well for $W^\pm Z$ production at the LHC by comparing to the full results.