Observation of the decay Λ0b→Λ+cppπ−

Abstract

The decay Λ0b→Λ+cppπ−is observed using ppcollision data collected with the LHCb detector at centre-of-mass energies of √s=7and 8Tev, corresponding to an integrated luminosity of 3fb−1. The ratio of branching fractions between Λ0b→Λ+cppπ−and Λ0b→Λ+cπ−decays is measured to be B(Λ0 b →Λ + c ppπ− ) B(Λ0 b →Λ + c π−) = 0.0540±0.0023±0.0032. Two resonant structures are observed in the Λ+cπ−mass spectrum of the Λ0b→Λ+cppπ−decays, corresponding to the Σc(2455)0and Σ∗c(2520)0states. The ratios of branching fractions with respect to the decay Λ0b→Λ+cppπ−are B(Λ0 b →Σ0 c pp)×B(Σ0 c →Λ + c π− ) B(Λ0 b →Λ + c ppπ−) = 0.089±0.015±0.006, B(Λ0 b →Σ ∗0 c pp)×B(Σ ∗0 c →Λ + c π− ) B(Λ0 b →Λ + c ppπ−) = 0.119±0.020±0.014. In all of the above results, the first uncertainty is statistical and the second is systematic. The phase space is also examined for the presence of dibaryon resonances. No evidence for such resonances is found.