Electroweak Precision Measurements with Leptons

Abstract

The precision measurements of lepton electroweak parameters at SLD and LEP are reviewed and discussed. The updated SLD weak mixing angle measurement from $A_{LR}$ and the lepton left-right forward-backward asymmetries is ${\sin }^2{\theta }_W^{eff}=0.23099\pm 0.00026$, and the combined SLD/LEP lepton-based value is $0.23119\pm 0.00020$. This value differs by over $3\sigma$ from the comparable quark-based value.

presented at the `International Europhysics Conference On High-Energy Physics' (EPS-HEP 99), Tampere, Finland, July, 1999