$\bar{D}{\Sigma }_c^{\ast }$ and ${\bar{D}}^{\ast }{\Sigma }_c$ interactions and the LHCb hidden-charmed pentaquarks

Abstract

Very recently, two hidden-charmed resonances $P_c(4380)$ and $P_c(4450)$ consistent with pentaquark states were observed at the LHCb detector. The two $P_c$ states locate just below the $\bar{D}{\Sigma }_c^{\ast }$ and ${\bar{D}}^{\ast }{\Sigma }_c$ thresholds with mass of gaps about 5 and 15 MeV, respectively. Inspired by this fact we perform a dynamical investigation about the $\bar{D}{\Sigma }_c^{\ast }(2520)$ and ${\bar{D}}^{\ast }{\Sigma }_c(2455)$ interactions which are described by the meson exchanges. A bound state which carries spin-parity $J^P=3/2^{-}$ is produced from the $\bar{D}{\Sigma }_c^{\ast }(2520)$ interaction, which is consistent with the $P_c(4380)$ observed at the LHCb detector. From the $D^{\ast }{\Sigma }_c(2455)$ interaction, a bound state with $5/2^{+}$ is produced, which can be related to the $P_c(4450)$. The results suggest that the $P_c(4380)$ and $P_c(4450)$ are good candidates of $\bar{D}{\Sigma }_c^{\ast }(2520)$ and ${\bar{D}}^{\ast }{\Sigma }_c(2455)$ molecular states, respectively.

Comments: 5 pages, 3 figures, published version in Phys. Lett. B