Eur. Phys. J. C (2025) 85: 1120
https://doi.org/10.1140/epjc/s10052-025-14845-z

Regular Article - Theoretical Physics

Pentaquarks $P_c$ in a dynamical coupled-channel approach of $\gamma p\to J/\psi p$ reaction

CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, 100190, Beijing, China

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Received: 2 June 2025
Accepted: 9 September 2025
Published online: 9 October 2025

Abstract

We construct a dynamical coupled-channel approach to photon-induced $J/\psi$ production to search for the trace of the pentaquarks $P_c.$ In this approach, the considered open-charm intermediate states are ${\mathrm{\Lambda }}_c{\overline{D}}^{(\ast )}$ and ${\mathrm{\Sigma }}_c{\overline{D}}^{(\ast )}.$ Scattering amplitude involving ${\mathrm{\Lambda }}_c{\overline{D}}^{(\ast )},$${\mathrm{\Sigma }}_c{\overline{D}}^{(\ast )}$ and $J/\psi p$ 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 $P_c$ are dynamically generated from the coupled-channel interactions. Moreover, the background contributions to the $P_c$ signals are assumed to be the Pomeron exchange and $\sigma$ exchange. We analyze the total and differential cross sections of $J/\psi$ photoproduction measured by the GlueX and $J/\psi$-007 experiments. It is found that both $\sigma$ 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.