Study of B¯→ΞcΛ¯c- and B¯→Λc+Λ¯c-K¯ decays at BABAR

We report measurements of B-meson decays into two- and three-body final states containing two charmed baryons using a sample of 230×106 Υ(4S)→BB̅ decays. We find significant signals in two modes, measuring branching fractions B(B-→Λc+Λ̅ c-K-)=(1.14±0.15±0.17±0.60)×10-3 and B(B-→Ξc0Λ̅ c-)×B(Ξc0→Ξ-π+)=(2.08±0.65±0.29±0.54)×10-5, where the uncertainties are statistical, systematic, and from the branching fraction B(Λc+→pK-π+), respectively. We also set upper limits at the 90% confidence level on two other modes: B(B̅ 0→Ξc+Λ̅ c-)×B(Ξc+→Ξ-π+π+)<5.6×10-5 and B(B̅ 0→Λc+Λ̅ c-K̅ 0)<1.5×10-3. We observe structure centered at an invariant mass of 2.93  GeV/c2 in the Λc+K- mass distribution of the decay B-→Λc+Λ̅ c-K-.