Sirunyan, A.M.Tumasyan, A.Adam, W.Ambrogi, F.Bergauer, T.Dragicevic, M.Ivanchenko, V.2020-07-182020-07-1820200370-2693https://doi.org/10.1016/j.physletb.2020.135203https://hdl.handle.net/11147/8457The observation of the Λb 0→J/ψΛϕ decay is reported using proton-proton collision data collected at s=13TeV by the CMS experiment at the LHC in 2018, corresponding to an integrated luminosity of 60fb−1. The ratio of the branching fractions B(Λb 0→J/ψΛϕ)/B(Λb 0→ψ(2S)Λ) is measured to be (8.26±0.90(stat)±0.68(syst)±0.11(B))×10−2, where the first uncertainty is statistical, the second is systematic, and the last uncertainty reflects the uncertainties in the world-average branching fractions of ϕ and ψ(2S) decays to the reconstructed final states. © 2020 The Authoreninfo:eu-repo/semantics/openAccessB PhysicsCmsComputingHeavy-Flavor SpectroscopyArticle2-s2.0-8507852900410.1016/j.physletb.2020.135203