Direct Measurement of Parity Violation in the Coupling of Z0 Bosons to b Quarks Using a Mass Tag and Momentum-Weighted Track Charge

We present a direct measurement of the parity-violation parameter Ab using a self-calibrating track-charge technique. In the SLAC Linear Collider Large Detector (SLD) experiment we observe hadronic decays of Z0 bosons produced in collisions between longitudinally polarized electrons and unpolarized positrons at the SLAC Linear Collider. A sample of bb¯ events is selected using the topologically reconstructed mass of B hadrons. From our 1993–1995 sample of approximately 150 000 hadronic Z0 decays, we obtain Ab=0.911±0.045(stat)±0.045(syst).