Study of the decay B̄0→Λc+p̄π+π- and its intermediate states

We study the decay B^0→Λ_c^+p π^+π^-, reconstructing the Λ_c^+ baryon in the pK^-π^+ mode, using a data sample of 467×10^6 BB pairs collected with the BABAR detector at the PEP-II storage rings at SLAC. We measure branching fractions for decays with intermediate Σ_c baryons to be B[B^0→Σ_c(2455)^(++)pπ^-]=(21.3±1.0±1.0±5.5)×10^(-5), B[B^0→Σ_c(2520)^(++)pπ^-]=(11.5±1.0±0.5±3.0)×10^(-5), B[B^0→Σ_c(2455)^0pπ^+]=(9.1±0.7±0.4±2.4)×10^(-5), and B[B^0→Σ_c(2520)^0pπ^+]=(2.2±0.7±0.1±0.6)×10^(-5), where the uncertainties are statistical, systematic, and due to the uncertainty on the Λ_c^+→pK^-π^+ branching fraction, respectively. For decays without Σ_c(2455) or Σ_c(2520) resonances, we measure B[B^0→Λ^c^+pπ^+π^-]_(non-)Σ_c= (79±4±4±20)×10^(-5). The total branching fraction is determined to be B[B^0→Λ_c^+pπ^+π^-]_(total)=(123±5±7±32)×10^(-5). We examine multibody mass combinations in the resonant three-particle Σ_cpπ final states and in the four-particle Λ_c^+pπ^+π^- final state, and observe different characteristics for the p π combination in neutral versus doubly charged Σ_c decays.