Search for a neutral gauge boson with nonuniversal fermion couplings in vector boson fusion processes in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports the first search for a heavy neutral gauge boson (Z') with nonuniversal fermion couplings produced via vector boson fusion at the LHC, setting mass exclusion limits up to 2.45 TeV based on 138 fb$^{-1}$ of data.

Contribution

It introduces a novel search strategy for Z' bosons with nonuniversal couplings in vector boson fusion processes at 13 TeV LHC data.

Findings

No evidence of Z' bosons found, consistent with Standard Model.

Excluded Z' masses up to 2.45 TeV for tau decay mode.

Excluded Z' masses up to 1.60 TeV for W boson decay mode.

Abstract

The first search for a heavy neutral spin-1 gauge boson (Z') with nonuniversal fermion couplings produced via vector boson fusion processes and decaying to tau leptons or W bosons is presented. The analysis is performed using LHC data at $\sqrt{s}$ = 13 TeV, collected from 2016 to 2018 and corresponding to an integrated luminosity of 138 fb$^{-1}$. The data are consistent with the standard model predictions. Upper limits are set on the product of the cross section for production of the Z' boson and its branching fraction to $\tau\tau$ or WW. The presence of a Z' boson decaying to $\tau^+\tau^-$ (W$^+$W$^-$) is excluded for masses up to 2.45 (1.60) TeV, depending on the Z' boson coupling to SM weak bosons, and assuming a Z' $\to$ $\tau^+\tau^-$ (W$^+$W$^-$) branching fraction of 50%.