A “no-lose” measurement of the hadronic and of the leptonic Z widths

We show that a high precision measurement of the full hadronic, of the leptonic Z₀ widths and of their ratio in the forthcoming run at LEP 1 might already allow, under realistic experimental conditions, to either discover clear evidence for New Physics of well identifiable origin or, at least, to set stringent bounds on the top mass valid in an extended, not “minimal”, standard model independently of the value of the parameter.