Polarized electroweak bosons in ${\bf \text{W}^+\text{W}^-}$ production at the LHC including NLO QCD effects

TL;DR

This paper calculates polarized W-boson pair production at the LHC, including NLO QCD effects, to improve the theoretical understanding of polarization measurements relevant for testing the Standard Model.

Contribution

It introduces a gauge-invariant method to define polarized signals in W-boson pair production and includes NLO QCD corrections and gluon-initiated processes for more accurate predictions.

Findings

Computed polarized cross-sections and distributions with NLO QCD corrections.

Identified variables suitable for experimental discrimination of polarization.

Provided results for inclusive and fiducial regions.

Abstract

The measurement of polarization fractions of massive gauge bosons at the LHC provides an important check of the Standard Model and in particular of the Electroweak Symmetry Breaking mechanism. Owing to the unstable character of $\text{W}$ and $\text{Z}$ bosons, devising a theoretical definition for polarized signals is not straightforward and always subject to some ambiguity. Focusing on $\text{W}$-boson pair production at the LHC in the fully leptonic channel, we propose to compute polarized cross-sections and distributions based on the gauge-invariant doubly-resonant part of the amplitude. We include NLO QCD corrections to the leading quark-induced partonic process and also consider the loop-induced gluon-initiated process contributing to the same final state. We present results for both an inclusive setup and a realistic fiducial region, with special focus on variables that are suited for the discrimination of polarized cross-sections and on quantities that can be measured experimentally.