Pole analysis on the hadron spectroscopy of Λb → J/ΨpK-

In this paper we study the J/psi p spectroscopy in the process of ?b -> J/psi pK-. The final state interactions of coupled channel J/psi p-D over bar sigma c-D over bar *sigma c are constructed based on K-matrix with the Chew-Mandelstam function. We build the ?b -> J/psi pK- amplitude according to the Au-Morgan-Pennington method. The event shape is fitted and the decay width of ?b -> J/psi pK- J/\Psi p K<^>-$$\end{document} is used to constrain the parameters, too. With the amplitudes we extract out the poles and their residues. Our amplitude and pole analysis suggest that the Pc(4312) should be D over bar sigma c molecule, the Pc(4440) could be an S-wave compact pentaquark state, and the structure around Pc(4457) is caused by the cusp effect. The future experimental measurement of the decays of ?b -> D over bar sigma cK- _c K<^>-$$\end{document} and ?b -> D over bar *sigma cK--$$\end{document} would further help to study the nature of these resonances.