Theoretical description of the decays Λb→Λ(*)(1/2±,3/2±)+J/ψ

We calculate the invariant and helicity amplitudes for the transitions Λb→Λ(*)(JP)+J/ψ, where the Λ(*)(JP) are Λ(sud)-type ground and excited states with JP quantum numbers JP=12±, 32±. The calculations are performed in the framework of a covariant confined quark model previously developed by us. We find that the values of the helicity amplitudes for the Λ∗(1520,32−) and the Λ∗(1890,32+) are suppressed compared with those for the ground state Λ(1116,12+) and the excited state Λ∗(1405,12−). This analysis is important for the identification of the hidden charm pentaquark states P+c(4380) and P+c(4450) which were discovered in the decay chain Λ0b→P+c(→pJ/ψ)+K−because the cascade decay chain Λb→Λ∗(32±)(→pK−)+J/ψ involves the same final state.