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[References: 21 tit.]

A study of the B+→J/ψΛ¯¯¯¯pB+→J/ψΛ¯p decay using proton-proton collision data collected at s√s = 8 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.6 fb−1, is presented. The ratio of branching fractions B(B+→J/ψΛ¯¯¯¯p)/B(B+→J/ψK∗(892)+)B(B+→J/ψΛ¯p)/B(B+→J/ψK∗(892)+) is measured to be (1.054 ± 0.057(stat) ± 0.035(syst) ± 0.011(BB))%, where the last uncertainty reflects the uncertainties in the world-average branching fractions of Λ¯¯¯¯Λ¯ and K*(892) + decays to reconstructed final states. The invariant mass distributions of the J/ψΛ¯¯¯¯J/ψΛ¯, J/ψp, and Λ¯¯¯¯pΛ¯p systems produced in the B+→J/ψΛ¯¯¯¯pB+→J/ψΛ¯p decay are investigated and found to be inconsistent with the pure phase space hypothesis. The analysis is extended by using a model-independent angular amplitude analysis, which shows that the observed invariant mass distributions are consistent with the contributions from excited kaons decaying to the Λ¯¯¯¯pΛ¯p system.