The SLD
collaboration has measured the left-right polarization
asymmetry in Z boson production (ALR) from a sample of
hadronic Z decays, and has measured the
left-right-forward-backward asymmetries in a sample of Z
decays to lepton pairs. (PRL, 84, 5945, 2000 and PRL,
86, 1162, 2001). The data are consistent with lepton
universality, and assuming this we combine the results
to derive a value of the effective weak mixing angle of
sinSQTHeff = 0.23098+-0.00026. With this result, a fit
to the Standard Model (SM), using the measured top quark
mass, Z mass, strong coupling constant, G_Fermi, and the
value of alpha(Mz**2) recently reported by Burkhardt and
Pietrzyk (LAPP-EXP 2001-03, February 2001) results in a
95% (99%) confidence level upper bound on the SM Higgs
Boson of 132 GeV (205 GeV). |