First observation of the Λ0 b → Λ+ c D− s K+K− decay and search for pentaquarks in the Λ+ c D− s system

Abstract

The Λ0 b → Λþ c D− s KþK− decay is observed for the first time using the data sample from proton-proton collisions recorded at a center-of-mass energy of 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 6 fb−1. The ratio of branching fraction to that of Λ0 b → Λþ c D− s decays is measured as 0.0141 0.0019 0.0012, where the first uncertainty is statistical and the second systematic. A search for hidden-charm pentaquarks with strangeness is performed in the Λþ c D− s system. No evidence is found, and upper limits on the production ratio of Pccs¯ ð4338Þ0 and Pccs¯ ð4459Þ0 pentaquarks relative to the Λþ c D− s final state are set at the 95% confidence level as 0.12 and 0.20, respectively