Z’ boson mass reach and model discrimination at muon colliders

Abstract

We study the discrimination power of future multi-TeV muon colliders for a large set of models with extended gauge symmetries and additional neutral gauge bosons (“$$Z'$$ Z ′ -models”). Our study is carried out using a $$\chi ^2$$ χ 2 -analysis of leptonic observables of s-channel scattering in effective $$Z'$$ Z ′ -models. We make use of angular and chiral asymmetries induced in such models to find the discovery reach of a given muon collider setup in terms of the $$Z'$$ Z ′ mass and to discriminate between the different scenarios. In this context, we discuss how polarized beams – should they become available at muon colliders – or polarization measurements can help in the discrimination. Our results show that typical muon collider setups which are currently under consideration can give a significantly higher reach compared to existing bounds and projections for high-luminosity LHC.