Search for a Neutral Gauge Boson with Nonuniversal Fermion Couplings in Vector Boson Fusion Processes in Proton-Proton Collisions at √s=13 TeV

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 root s = 13 TeV, collected from 2016 to 2018 with the CMS experiment 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 standard model weak bosons, and assuming a Z ' -> tau(+)tau(-) (W+W-) branching fraction of 50%.