Pentaquarks Pc in a dynamical coupled-channel approach of γ p → J/ψ p reaction

We construct a dynamical coupled-channel approach to photon-induced J/ψ J / ψ production to search for the trace of the pentaquarks Pc. P c . In this approach, the considered open-charm intermediate states are Λ c D̄(*) Λ c D ¯ ( ∗ ) and Σ c D̄(*). Σ c D ¯ ( ∗ ) . Scattering amplitude involving Λ c D̄(*), Λ c D ¯ ( ∗ ) , Σ c D̄(*) Σ c D ¯ ( ∗ ) and J/ψ p J / ψ p interactions is calculated from solving a set of coupled-channel integral equations. The coupled-channel interaction potentials are generated from one-boson-exchange. The pentaquarks Pc P c are dynamically generated from the coupled-channel interactions. Moreover, the background contributions to the Pc P c signals are assumed to be the Pomeron exchange and σ σ exchange. We analyze the total and differential cross sections of J/ψ J / ψ photoproduction measured by the GlueX and J/ψ J / ψ -007 experiments. It is found that both σ σ exchange and open-charm state rescattering have contributions in describing the total and differential cross section. The total cross section gets enhanced due to the open-charm state rescattering in the pentaquark production regions, and is of order 1 nb or smaller.