# Constraining $Z^\prime$ widths from $p_T$ measurements in Drell-Yan processes

## TL;DR

This paper introduces a novel asymmetry measure in Drell-Yan processes, called the Focus Point (FP) Asymmetry, which is highly sensitive to the $Z^\prime$ width and can help constrain it experimentally.

## Contribution

The paper proposes the FP Asymmetry based on the transverse momentum distribution, providing a new method to constrain $Z^\prime$ widths in collider experiments.

## Key findings

- The FP position depends only on collider energy and low transverse momentum cut.
- The FP Asymmetry is highly sensitive to the $Z^\prime$ width.
- This method can improve experimental constraints on $Z^\prime$ models.

## Abstract

We define a Focus Point (FP) Asymmetry, $A_{\rm FP}$, obtained by integrating the normalised transverse momentum distribution of either lepton produced in the Drell-Yan (DY) process below and above a point where a variety of popular $Z^\prime$ models all have the same magnitude. For a given $Z^\prime$ mass the position of this FP is predictable, depending only on the collider energy and on the low transverse momentum cut chosen in the normalisation procedure. The resulting $A_{\rm FP}$ is very sensitive to the $Z^\prime$ width, and can be used to constrain this parameter in experimental fits.