Decay behaviors of the Pc hadronic molecules

The P_c(4380 ) and P_c(4450 ) states observed recently by the LHCb experiment were proposed to be either D ¯Σ_c^* or D^¯*Σ_c bound states. We analyze the decay behaviors of two such types of hadronic molecules within the effective Lagrangian framework. With branching ratios of ten possible decay channels calculated, it is found that the two types of hadronic molecules have distinguishable decay patterns. While the D ¯Σ_c^* molecule decays dominantly to the D^¯*Λ_c channel with a branching ratio by 2 orders of magnitude larger than to D ¯Λ_c, the D^¯*Σ_c molecule decays to these two channels with a difference of less than a factor of 2. Our results show that the total decay width of P_c(4380 ) as the spin-parity-3/2^- D ¯Σ_c^* molecule is about a factor of 2 larger than the corresponding value for the D^¯*Σ_c molecule. It suggests that the assignment of the D ¯Σ_c^* molecule for P_c(4380 ) is more favorable than the D^¯*Σ_c molecule. In addition, P_c(4450 ) seems to be a D^¯*Σ_c molecule with J^P=5/2⁺ in our scheme. Based on these partial decay widths of the P_c states, we estimate the cross sections for the reactions γ p →J /ψ p and π p →J /ψ p through the s-channel P_c states. The forthcoming γ p experiment at JLAB and the π p experiment at JPARC should be able to pin down the nature of these P_c states.