A measurement of the semileptonic branching ratio $BR(b-baryon \to pl\overline{\nu}X$) and a study of inclusive particle production in Z decays

Inclusive pi /sup +or-/, K/sup +or-/ 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 to bb, Z to cc and Z to uu, 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+or-0.7+or-2.7)% assuming BR(b- baryon to pX)=(58+or-6)%. From an additional study of proton-lepton correlations in b events, the branching ratio BR(b-baryon to pl nu X) =(4.63+or-0.72+or-0.98)% is obtained. The ratio BR(b-baryon to pl nu X)/BR(b-baryon to pX) is found to be 0.080+or-0.012+or-0.014. (12 refs).