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

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 pair and total hadronic cross sections measured at KEK TRISTAN. A detailed comparison is made between the MW and MZ 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 MW and MZ data, and set lower bounds on the Z mass from direct production searches at the Collider Detector at Fermilab (CDF). We analyze the effects of Z-Z mixing on the Z width, leptonic branching ratio, and peak cross section at e+e- colliders. We find that a second Z cannot account for the increase in total hadronic and decrease in -pair cross sections observed at KEK TRISTAN and simultaneously satisfy the CDF Z search limits.