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

Abstract

: A search is performed for the as yet unobserved baryonic Λ0 b → Λη 0 and Λ 0 b → Λη decays with 3 fb−1 of proton-proton collision data recorded by the LHCb experiment. The B0 → K0 sη 0 decay is used as a normalisation channel. No significant signal is observed for the Λ0 b → Λη 0 decay. An upper limit is found on the branching fraction of B(Λ0 b → Λη 0 ) < 3.1 × 10−6 at 90% confidence level. Evidence is seen for the presence of the Λ0 b → Λη decay at the level of 3σ significance, with a branching fraction B(Λ0 b → Λη) = (9.3 +7.3 −5.3 ) × 10−6 .