A Measurement of the Branching Ratio R(B) = Gamma (Z(0) --> B Anti-B)/Gamma (Z(0) --> Hadrons) Using a Minimum Missing P(T) Corrected Mass Tag

Presented here is a new measurement of R{sub b} = {Lambda}(Z{sup 0} {yields} b{bar b})/{Lambda}(Z{sup 0} {yields} hadrons) using a self-calibrating double tag technique where the b selection is based on topological and kinematic reconstruction of the mass of the B-decay vertex. The measurement was performed using a sample of 72074 hadronic Z{sup 0} events out of the 150 k hadronic Z{sup 0} decays collected with the SLD at the SLAC Linear Collider during 1993-1995. The method utilizes the 3-D vertexing abilities of the SLD CCD pixel vertex detector and the small stable SLC beams to obtain a high b tagging efficiency of 35.3% for a purity of 98.0%. The high purity reduces the systematic uncertainty introduced by charm contamination and correlations with R{sub c}. They obtain a result of R{sub b} = 0.2142 {+-} 0.0034{sub stat.} {+-} 0.0015{sub syst.} {+-} 0.0002{sub R{sub b}} (corrected for the e{sup +}e{sup -} {yields} {gamma} exchange contribution).