CORRELATION BETWEEN MZ' AND MT BOUNDS .1. NEUTRAL CURRENT DATA

We discuss present neutral current data constraints (combined with M(w) and M(Z) measurements) on m(t) (and m(H)) in the minimal gauge extension of the standard model. The extra gauge boson mass M(Z'), is the only new parameter (for fixed new gauge couplings-lambda and theta-1). Fits performed with M(Z'), and m(t) free, translate into allowed regions in the M(Z'),-m(t) plane where the M(Z'), lower bound is correlated with the m(t) upper bound. As a consequence, the m(t) upper bound in extended electroweak models is stronger (lower) than the one obtained in the minimal standard model, and coincides with it in the limits M(Z'), --> infinity. The influence of the different pieces of data on the fits is also discussed. We briefly comment on other constraints, such as those from charged current data and direct production at large hadron colliders.