We present the measurements of the leptonic asymmetries in $Z^0$ decays measured by the SLD experiment at SLAC. A data sample of approximately 550,000 $Z^0$ bosons are used for the preliminary measurement of $A_{ LR}(A_{ e})$ and the leptonic final state measurements of $A_{ e}$, $A_{ \mu}$ and $A_{ \tau}$, representing the entire set of 1992-1998 SLD runs. When combining all results, a preliminary value for the effective weak mixing angle is obtained: ${ \sin}^2{ \theta}_{ W}^{ eff} = 0.23109 \pm 0.00029$. We also present the direct measurements of $A_{ b}$ from left-right forward-backward asymmetries, using partial data samples from 1993-1998 SLD runs. The preliminary value combines jet charge, cascade kaon and semileptonic decay analyses to obtain $A_{ b} = 0.866 \pm 0.036$.
Categories: hep-ex