A heavy neutral gauge boson near the Z boson mass pole via third generation fermions at the LHC

TL;DR

This paper investigates a new neutral gauge boson ($Z'$) near the Z boson mass, produced via third-generation fermions at the LHC, and demonstrates the collider's potential to constrain such models through top quark processes.

Contribution

It introduces a search strategy for a $Z'$ boson coupling to third-generation fermions, showing LHC's capability to set limits on right-handed top couplings in this context.

Findings

LHC can effectively exclude $Z'$ models near the Z mass with current data.

The $t\bar{t}Z'$ process constrains right-handed top couplings.

High-luminosity LHC improves sensitivity to third-generation $Z'$ couplings.

Abstract

We explore the physics of a new neutral gauge boson, ($Z^\prime$), coupling to only third-generation particles with a mass near the electroweak gauge boson mass poles. A $Z^\prime$ boson produced by top quarks and decaying to tau leptons is considered. With a simple search strategy inspired by existing analyses of the standard model gauge boson production in association with top quarks, we show that the Large Hadron Collider has good exclusionary power over the model parameter space of the $Z^\prime$ boson even at the advent of the high-luminosity era. It is shown that the $t\bar{t}Z^\prime$ process allows one to place limits on right-handed top couplings with a $Z^\prime$ boson that preferentially couples to third generation fermions, which are at present very weakly constrained.