Observation of the Λ0b → Λ+c K + K −π− decay

The Λ0b → 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 TeV collected by the LHCb detector, corresponding to an integrated luminosity of 3fb−1 . The ratio of branching fractions between the Λ0b → Λ+c K + K −π−
and the Λ0b → Λ+c D−s decays is measured to be
B(Λ0b → Λ+c K + K −π−)B(Λ0b → 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.