UPDATED ANALYSIS OF HIGH-PRECISION LEP DATA

The precision electroweak data presented by the LEP Collaborations at La Thuile and Moriond Conferences in March 1993 are analyzed in a mult iparameter framework that allows inclusion of a large category of exte nsions of the minimal SU(2)L x U(1) Standard Model. The main conclusio ns are: (i) The data agree well with the Minimal Standard Model (MSM); (ii) The best fit to the top quark and Higgs boson masses in the MSM is M(t) = 143 +/- 19/18 GeV, M(H) = 73 +/- 178/13 GeV. The positive er ror on M(H) is gaussian in log(M(H)). The data favor somewhat the ligh ter Higgs boson mass range but still agrees with M(H) = 1000 GeV withi n less than two standard deviations. (iii) The new results on GAMMA(b) /GAMMA(had) now play a fundamental role in deriving a DELTArho and M(H )-independent top quark mass limit from the Z --> bbBAR vertex correct ion. So far this limit was mostly obtained from R(had) and was intimat ely dependent on the value chosen for the strong coupling constant. Wi th all data we find, for alpha(s) (M(Z)2) = 0.117 +/- 0.005, M(t) < 18 5 GeV at 95% CL, DELTArho and M(H) independent. As a consequence of th is new precision on GAMMA(b)/GAMMA(had), it is possible to derive from electroweak measurements a value of alpha(s) (M(Z)2), even with all t he electroweak parameters left free outside the MSM range: alpha(s) (M (Z)2) = 0.111 +/- 0.015.