Understanding Pcs (4459) as a hadronic molecule in the Ξb- →j /ψ Λk- decay

Recently, the LHCb Collaboration reported on the evidence for a hidden charm pentaquark state with strangeness, i.e., Pcs(4459), in the J/ψΛ invariant mass distribution of the Ξb-→J/ψΛK- decay. In this work, assuming that Pcs(4459) is a D¯∗Ξc molecular state, we study this decay via triangle diagrams Ξb→D¯s(∗)Ξc→(D¯(∗)K̄)Ξc→PcsK̄→(J/ψΛ)K̄. Our study shows that the production yield of a spin 3/2 D¯∗Ξc state is approximately one order of magnitude larger than that of a spin 1/2 state due to the interference of D¯sΞc and D¯s∗Ξc intermediate states. We obtain a model independent constraint on the product of couplings gPcsD¯∗Ξc and gPcsJ/ψΛ. With the predictions of two particular molecular models as inputs, we calculate the branching ratio of Ξb-→(Pcs→)J/ψΛK- and compare it with the experimental measurement. We further predict the line shape of this decay that could be useful to future experimental studies.