Measurement of the b baryon lifetime and branching fractions in Z decays

Using approximately 4 million hadronic Z decays recorded with the aleph detector from 1991 through 1995, the lifetime of the b baryon is measured with three independent methods. From the impact parameter distribution of candidate leptons in 1063 events with combinations, the average b baryon lifetime is measured to be ps. From a sample of 193 fully reconstructed candidates correlated with a lepton and a sample of 46 combinations, the lifetime is measured to be ps. The product branching fractions to these final states are % for the first sample and % for the second and third samples combined.