Study of the decay B¯0→Λc+p¯π+π- and its intermediate states

Abstract

We study the decay ¯¯¯ B 0 → Λ + c ¯ p π + π − , reconstructing the Λ + c baryon in the p K − π + mode, using a data sample of 467 × 10 6 B ¯¯¯ B 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 ) ++ ¯ p π − ] = ( 21.3 ± 1.0 ± 1.0 ± 5.5 ) × 10 − 5 , B [ ¯¯¯ B 0 → Σ c ( 2520 ) ++ ¯ p π − ] = ( 11.5 ± 1.0 ± 0.5 ± 3.0 ) × 10 − 5 , B [ ¯¯¯ B 0 → Σ c ( 2455 ) 0 ¯ p π + ] = ( 9.1 ± 0.7 ± 0.4 ± 2.4 ) × 10 − 5 , and B [ ¯¯¯ B 0 → Σ c ( 2520 ) 0 ¯ p π + ] = ( 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 → p K − π + branching fraction, respectively. For decays without Σ c ( 2455 ) or Σ c ( 2520 ) resonances, we measure B [ ¯¯¯ B 0 → Λ + c ¯ p π + π − ] non − Σ c = ( 79 ± 4 ± 4 ± 20 ) × 10 − 5 . The total branching fraction is determined to be B [ ¯¯¯ B 0 → Λ + c ¯ p π + π − ] total = ( 123 ± 5 ± 7 ± 32 ) × 10 − 5 . We examine multibody mass combinations in the resonant three-particle Σ c ¯ p π final states and in the four-particle Λ + c ¯ p π + π − final state, and observe different characteristics for the ¯ p π combination in neutral versus doubly charged Σ c decays.