Measurements of the Left-Right Asymmetry in Z Boson Events at SLAC.

Recent results from the 1992 and 1993 left-right asymmetry cross section measurements at the Stanford Linear Accelerator Center are presented. Measurements made with SLAC running with a center-of-mass energy at the Z ^0-pole (91.2 GeV) by the SLD detector and an average electron beam polarization of 22.4 +/- 0.7% for 1992 and 62.6 +/- 1.2% for 1993. The asymmetry measured was A _{LR} = 0.100 +/- 0.044 and A_{LR } = 0.1656 +/- 0.0073 for the 1992 and 1993 runs, respectively. This in turn allows us to calculate the weak mixing angle value of sin ^2 theta_{w } = 0.2378 +/- 0.0056 and sin^2 theta_ {w} = 0.2288 +/- 0.0009 for the two data sets.