Search for the Λ 0b → Λη ′ and Λ 0b → Λη decays with the LHCb detector

Abstract

A search is performed for the as yet unobserved baryonic Λ 0b → Λη ′ and Λ 0b → Λη decays with 3 fb−1 of proton-proton collision data recorded by the LHCb experiment. The B0 → K 0sη ′ decay is used as a normalisation channel. No significant signal is observed for the Λ 0b → Λη ′ decay. An upper limit is found on the branching fraction of B(Λ0b→Λη′) < 3.1 × 10−6 at 90% confidence level. Evidence is seen for the presence of the Λ 0b → Λη decay at the level of 3σ significance, with a branching fraction B(Λ0b→Λη)=(9.3+7.3−5.3)×10−6