Observation of the Λb0→Λc+K+K−π− decay

Abstract The Λ b 0 → Λ c + K + K − π − decay is observed for the first time using a data sample of proton-proton collisions at centre-of-mass energies of s = 7 and 8 Te V collected by the LHCb detector, corresponding to an integrated luminosity of 3 f b − 1 . The ratio of branching fractions between the Λ b 0 → Λ c + K + K − π − and the Λ b 0 → Λ c + D s − decays is measured to be B ( Λ b 0 → Λ c + K + K − π − ) B ( Λ b 0 → Λ c + D s − ) = ( 9.26 ± 0.29 ± 0.46 ± 0.26 ) × 10 − 2 , where the first uncertainty is statistical, the second systematic and the third is due to the knowledge of the D s − → K + K − π − branching fraction. No structure on the invariant mass distribution of the Λ c + K + system is found, consistent with no open-charm pentaquark signature.