Theoretical description of the decays Λb → Λ (∗) (12 ±, 32 ±)+J /ψ THEORETICAL DESCRIPTION of the DECAYS THOMAS GUTSCHE et al.

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 Pc+(4380) and Pc+(4450) which were discovered in the decay chain Λb0→Pc+(→pJ/ψ)+K- because the cascade decay chain Λb→Λ∗(32±)(→pK-)+J/ψ involves the same final state.