Chiral Couplings of W' and Top Quark Polarization at the LHC

TL;DR

This paper discusses methods to determine the chiral couplings of a hypothetical W' boson to standard model fermions at the LHC by analyzing top quark polarization and decay distributions.

Contribution

It introduces a reconstruction technique for W' decays and identifies key kinematic observables to distinguish the chiral nature of W' couplings.

Findings

Top quark polarization effectively probes W' chiral couplings.

Analytical and numerical methods validate the observables.

Angular distributions reveal coupling chirality.

Abstract

If a TeV-scale charged gauge boson (W') is discovered at the Large Hadron Collider (LHC), it will become imperative to determine its chiral couplings to standard model (SM) fermions in order to learn about the underlying theory containing the W'. We describe the reconstruction of the t, b decay mode of the W' at the LHC, and identify various kinematic observables such as the angular distributions of the top quark and the lepton resulting from top decay that can be used to disentangle the chiral couplings of the W' to SM fermions. We demonstrate by presenting analytical expressions, numerical simulations, as well as intuitive illustrations for these observables at the LHC that among the SM fermions, the polarized top quark can most directly probe the chirality of such couplings.