Evidence for charmed baryons inB-meson decay

Abstract

We report on new measurements of the Λ and proton branching fractions and momentum spectra from B-meson decay. The large Λ-to-p ratio, the absence of B→ΛΛ¯X, and the presence of Λ-lepton charge correlations suggest that charmed baryons are produced in B decay. Under the assumption that all of the observed baryons are associated with charmed-baryon production, we find a B–to–charmed-baryon branching fraction of (7.4±2.9)%.