Improved measurement of the probability for gluon splitting into b(b)over-bar in Z(0) decays

Abstract We have measured gluon splitting into bottom quarks, g→b b , in hadronic Z 0 decays collected by SLD between 1996 and 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. 4-jet events were identified, and in each event a topological vertex-mass technique was applied to the two jets closest in angle in order to identify them as b or b jets. The upgraded CCD-based vertex detector gives very high B -tagging efficiency, especially for B hadrons with the low energies typical of this process. We measured the rate of g→b b production per hadronic event, g b b , to be (2.44±0.59(stat.)±0.34(syst.))×10 −3 .