Bounds on new Z bosons.

Abstract

Since new $Z$ bosons (${Z}^{\ensuremath{'}}$) are predicted by many approaches to particle physics beyond the standard model, the absence of a signal in lepton pairs at hadron colliders implies important, but very model-dependent, lower limits on ${Z}^{\ensuremath{'}}$ masses. We present an analytical procedure for converting an experimental limit on $\ensuremath{\sigma}({Z}^{\ensuremath{'}})B({Z}^{\ensuremath{'}}\ensuremath{\rightarrow}{l}^{+}{l}^{\ensuremath{-}})$ into mass limits in a large set of models. Explicit results are given for present CERN and future Fermilab collider data. We include renormalization effects so that consideration can be restricted to grand-unification models.