Electroweak gauge boson polarisation at the LHC

TL;DR

This paper investigates the polarization states of W and Z gauge bosons produced at the LHC, analyzing how their polarization affects angular and momentum distributions across various production processes.

Contribution

It provides a comprehensive analysis of gauge boson polarization effects in different LHC processes, including W and Z production, highlighting process-dependent polarization characteristics.

Findings

Polarization influences angular and momentum distributions of decay leptons.

Different production processes show distinct polarization patterns.

Kinematic cuts impact the observed polarization effects.

Abstract

We study the polarisation of gauge bosons produced at the LHC. Polarisation effects for W bosons manifest themselves in the angular distributions of the lepton and in the distributions of lepton transverse momentum and missing transverse energy. The distributions also depend on the selection cuts, with kinematic effects competing with polarisation effects. The polarisation is discussed for a range of different processes producing W bosons: W+jets, W from top (single and pair) production, W pair production and W production in association with a Z or Higgs boson. The relative contributions of the different polarisation states varies from process to process, reflecting the dynamics of the underlying hard-scattering process. We also present results for the polarisation of the Z boson produced in association with QCD jets at the LHC, and comment on the differences between W and Z production.