Combined SLD Measurement of Ab at the Z Resonance using Various Techniques

Abstract

We present a new preliminary combination of measurements of the parity-violation parameter Ab made by the SLD collaboration using various experimental techniques. The techniques differ in detail, but in general a sample of bb events is selected or enhanced by using the topologically reconstructed mass of the separated vertices formed by decaying B hadrons. The direction of the b(bbar) quark is signed by one of four final state tags: jet charge, vertex charge, leptons, or identified K+- from the b vertex. We account for statistical and systematic correlations between the four analyses to arrive at our combined result: Ab=0.905 +/- 0.017 {stat} +/- 0.020 (syst).