Z 0 Pole Measurements of Parity Violation Parameters a B and a C at Slccsld

SLC/SLD provides the ideal experimental environment to directly measure the parity violation parameters at the Zbb, Zcc vertex decays. Three di erent analysis techniques exploit the multi-purpose detector capabilities and are brie y described; the updated result obtained with the semileptonic decay method is presented. Presented at the 28th International Conference on High Energy Physics Warsaw (Poland) July 25-31, 1996 Work supported by Department of Energy contracts: DE-FG02-91ER40676 (BU), DEFG03-91ER40618 (UCSB), DE-FG03-92ER40689 (UCSC), DE-FG03-93ER40788 (CSU), DE-FG02-91ER40672 (Colorado), DE-FG02-91ER40677 (Illinois), DE-AC03-76SF00098 (LBL), DE-FG02-92ER40715 (Massachusetts), DE-AC02-76ER03069 (MIT), DE-FG0685ER40224 (Oregon), DE-AC03-76SF00515 (SLAC), DE-FG05-91ER40627 (Tennssee), DE-FG02-95ER40896 (Wisconsin), DE-FG02-92ER40704 (Yale); National Science Foundation grants: PHY-91-13428 (UCSC), PHY-89-21320 (Columbia), PHY-92-04239 (Cincinnati), PHY-88-17930 (Rutgers), PHY-88-19316 (Vanderbilt), PHY-92-03212 (Washington); the UK Science and Engineering Research Council (Brunel and RAL); the Istituto Nazionale di Fisica Nucleare of Italy (Bologna, Ferrara, Frascati, Pisa, Padova, Perugia); and the Japan-US Cooperative Research Project on High Energy Physics (Nagoya, Tohoku). The SLD Collaboration authors and their institutions are listed following the references.