Molecule pictures for the LHCb P_c states

The first two pentaquark candidates P_c(4380) and P_c(4450) were observed by LHCb Collaboration in 2015. Recently, they presented their improved measurements in the P_c energy range, that a new narrow signal denoted as P_c(4312) is reported and the previous observed structure P_c(4450) is resolved into two narrow states, P_c(4440) and P_c(4457) while there is no obvious signal for the broad state P_c(4380). We analyze the strong decays of these P_c states systematically in the hadronic molecule pictures. With the effective Lagrangian method, the partial widths of these P_c decaying into all allowed channels are estimated. Our results show that these P_c states are good candidates of the S-wave $\overline{D}{\mathrm{\Sigma }}_c,\overline{D}{\mathrm{\Sigma }}_c^{*}$ and $\overline{D}*{\mathrm{\Sigma }}_c$ molecules. Also other possible flavor and spin partners of P_c states are investigated in the present work.