Pole analysis on the hadron spectroscopy of Lambda _brightarrow J/Psi p K^-

Abstract

In this paper we study the J/Psi p spectroscopy in the process of Lambda _brightarrow J/Psi p K^-. The final state interactions of coupled channel J/Psi p–bar{D} Sigma _c–bar{D}^{*} Sigma _c are constructed based on K-matrix with the Chew–Mandelstam function. We build the Lambda _brightarrow J/Psi p K^- amplitude according to the Au–Morgan–Pennington method. The event shape is fitted and the decay width of Lambda _brightarrow J/Psi p K^- 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 P_c(4312) should be bar{D}Sigma _c molecule, the P_c(4440) could be an S-wave compact pentaquark state, and the structure around P_c(4457) is caused by the cusp effect. The future experimental measurement of the decays of Lambda _brightarrow bar{D}Sigma _c K^- and Lambda _brightarrow bar{D}^*Sigma _c K^- would further help to study the nature of these resonances.