Radiative corrections to W,Z masses and constraints on new Z bosons.

Abstract

We explore the implications of the recent $W$- and $Z$-boson-mass measurements at the SLAC Linear Collider, CERN LEP, and Fermilab Tevatron, and also the $\ensuremath{\mu}$ pair and total hadronic cross sections measured at KEK TRISTAN. A detailed comparison is made between the ${M}_{W}$ and ${M}_{Z}$ data and standard-model predictions including radiative corrections. These measurements also constrain extended electroweak gauge models. We place model-dependent upper bounds on the mass of a second neutral gauge boson from ${M}_{W}$ and ${M}_{Z}$ data, and set lower bounds on the ${Z}^{\ensuremath{'}}$ mass from direct production searches at the Collider Detector at Fermilab (CDF). We analyze the effects of $Z\ensuremath{-}{Z}^{\ensuremath{'}}$ mixing on the $Z$ width, leptonic branching ratio, and peak cross section at ${e}^{+}{e}^{\ensuremath{-}}$ colliders. We find that a second $Z$ cannot account for the increase in total hadronic and decrease in $\ensuremath{\mu}$-pair cross sections observed at KEK TRISTAN and simultaneously satisfy the CDF ${Z}^{\ensuremath{'}}$ search limits.