Direct Measurement of A[sub b] and A[sub c] at the Z[sup 0] Pole Using a Lepton Tag

The parity violation parameters A[sub b] and A[sub c] of the Zb[ovr b] and Zc[ovr c] couplings have been measured directly, using the polar angle dependence of the Z[sup 0] -pole polarized cross sections. Bottom and charmed hadrons were tagged via semileptonic decays. Both the muon and electron identification algorithms take advantage of new multivariate techniques, incorporating for the first time information from the SLD [hacek C]erenkov Ring Imaging Detector. Based on the 1993[endash]1995 SLD sample of 150thinsp000 Z[sup 0] decays produced with highly polarized electron beams, we measure A[sub b]=0.910[plus minus]0.068(stat) [plus minus]0.037(syst) , A[sub c]=0.642[plus minus]0.110(stat) [plus minus]0.063(syst) . [copyright] [ital 1999] [ital The American Physical Society ]