Anatomy of the newly observed hidden-charm pentaquark states: Pc(4312), Pc(4440) and Pc(4457)

Abstract

We study the newly reported hidden-charm pentaquark candidates Pc(4312), Pc(4440) and Pc(4457) from the LHCb Collaboration, in the framework of the effective-range expansion and resonance compositeness relations. The scattering lengths and effective ranges from the S-wave ΣcD¯ and ΣcD¯⁎ scattering are calculated by using the experimental results of the masses and widths of the Pc(4312), Pc(4440) and Pc(4457). Then we calculate the couplings between the J/ψp,ΣcD¯ channels and the pentaquark candidate Pc(4312), with which we further estimate the probabilities of finding the J/ψp and ΣcD¯ components inside Pc(4312). The partial decay widths and compositeness coefficients are calculated for the Pc(4440) and Pc(4457) states by including the J/ψp and ΣcD¯⁎ channels. Similar studies are also carried out for the three Pc states by including the ΛcD¯⁎ and ΣcD¯(⁎) channels.