# The Determination of the Helicity of $W'$ Boson Couplings at the LHC

## TL;DR

This paper investigates how the LHC can determine the helicity of $W'$ boson couplings using the transverse mass distribution in the $ ext{l} + E_T^{miss}$ channel, requiring specific luminosities for different $W'$ masses.

## Contribution

It demonstrates that the transverse mass distribution in the interference region effectively measures $W'$ helicity at low luminosities, with potential improvements from leptonic asymmetries.

## Key findings

- Transverse mass distribution provides the best helicity measurement.
- Luminosity requirements are ~10 fb^{-1} for 1.5 TeV and ~60 fb^{-1} for 2.5 TeV $W'$ masses.
- Helicity determination is feasible with current LHC capabilities.

## Abstract

Apart from its mass and width, the most important property of a new charged gauge boson, $W'$, is the helicity of its couplings to the SM fermions. Such particles are expected to exist in many extensions of the Standard Model. In this paper we explore the capability of the LHC to determine the $W'$ coupling helicity at low integrated luminosities in the $\ell +E_T^{miss}$ discovery channel. We find that measurements of the transverse mass distribution, reconstructed from this final state in the $W-W'$ interference region, provides the best determination of this quantity. To make such measurements requires integrated luminosities of $\sim 10(60) fb^{-1}$ assuming $M_{W'}=1.5(2.5)$ TeV and provided that the $W'$ couplings have Standard Model magnitude. This helicity determination can be further strengthened by the use of various discovery channel leptonic asymmetries, also measured in the same interference regime, but with higher integrated luminosities.