A Measurement of the semileptonic branching ratio BR(b-baryon ---> p lepton anti-neutrino X) and a study of inclusive pi+-, K+-, (p,anti-p) production in Z decays

Inclusive π± , K± and ( p,p¯ ) production is investigated using data recorded by the aleph detector between 1992 and 1994. The momentum spectra and multiplicities are measured separately in Z→bb¯ , Z→cc¯ and Z→u\baru,dd¯,ss¯ decays. The number of protons found in b-hadron decays is used to estimate the fraction of b-baryons in b events to be (10.2±0.7±2.7)% assuming BR(b-baryon →pX)=(58±6)% . From an additional study of proton-lepton correlations in b events, the branching ratio BR(b-baryon→plν¯X)=(4.63±0.72±0.98)% is obtained. The ratio BR(b-baryon→plν¯X)/BR(b-baryon→pX) is found to be 0.080±0.012±0.014 .