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A study of Bbar -> Xi_c Lambda_c^- and Bbar -> Lambda_c^+ Lambda_c^- Kbar 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 million Y(4S) -> B Bbar decays. We find significant signals in two modes, measuring branching fractions BF(B^- -> Λ_c^+ Λ_c^- K^-) = (1.14 +- 0.15 +- 0.17 +- 0.60) x 10^{-3} and BF(B^- -> Ξ_c^0 Λ_c^-) x BF(Ξ_c^0 -> Ξ^- π^+) = (2.08 +- 0.65 +- 0.29 +- 0.54) x 10^{-5}, where the uncertainties are statistical, systematic, and from the branching fraction BF(Λ_c^+ -> p K^- π^+), respectively. We also set upper limits at the 90% confidence level on two other modes: BF(B0bar -> Ξ_c^+ Λ_c^-) x BF(Ξ_c^+ -> Ξ^- π^+ π^+) < 5.6 x 10^{-5} and BF(B0bar -> Λ_c^+ Λ_c^- K0bar) < 1.5 x 10^{-3}. We observe structure centered at an invariant mass of 2.93 GeV/c^2 in the Λ_c^+ K^- mass distribution of the decay B^- -> Λ_c^+ Λ_c^- K^-.