Hidden charm pentaquark states and $\Sigma_c^{(*)}\bar{D}^{(*)}$ interaction in chiral perturbation theory

Abstract

We adopt the chiral perturbation theory to calculate the $\Sigma_{c}^{(*)}\bar{D}^{(*)}$ interaction to the next-to-leading order (NLO) and include the couple-channel effect in the loop diagrams. We reproduce the three $P_c$ states in the molecular picture after including the $\Lambda_{c}\bar{D}^{(*)}$ intermediate states. We also discuss some novel observations arising from the loop diagrams.