Observation of the baryonic B-decay B̄0→Λc+p̄K-π+

We report the observation of the baryonic B-decay B0→Λ c+pK-π+, excluding contributions from the decay B0→Λ c+ΛK-. Using a data sample of 467×106 BB pairs collected with the BABAR detector at the PEP-II storage ring at SLAC, the measured branching fraction is (4.33±0.82stat±0.33syst±1. 13Λc+)×10-5. In addition we find evidence for the resonant decay B0→Σc(2455)++pK- and determine its branching fraction to be (1.11±0.30stat±0.09syst±0.29Λc+)×10-5. The errors are statistical, systematic, and due to the uncertainty in the Λc+ branching fraction. For the resonant decay B0→Λc+p K*0 we obtain an upper limit of 2.42×10-5 at 90% confidence level. © 2009 The American Physical Society.