Possible pentaquarks with heavy quarks

Abstract

Inspired by the discovery of two pentaquarks $P_c(4380)$ and $P_c(4450)$ at the LHCb detector, we study possible hidden-charm molecular pentaquarks in the framework of quark delocalization color screening model. Our results suggest that both $N{\eta }_c$ with $I{J}^P=\frac{1}{2}{\frac{1}{2}}^{-}$ and $NJ/\psi$ with $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$ are bounded by channels coupling. However, $NJ/\psi$ with $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$ may be a resonance state in the $D-$wave $N{\eta }_c$ scattering process. Moreover, $P_c(4380)$ can be explained as the molecular pentaquark of ${\Sigma }_c^{\ast }D$ with quantum numbers $I{J}^P=\frac{1}{2}{\frac{3}{2}}^{-}$. The state ${\Sigma }_c^{\ast }{D}^{\ast }$ with $I{J}^P=\frac{1}{2}{\frac{5}{2}}^{-}$ is a resonance, it may not be a good candidate of the observed $P_c(4450)$ because of the opposite parity of the state to $P_c(4380)$, although the mass of the state is not far from the experimental value. In addition, the calculation is extended to the hidden-bottom pentaquarks, the similar properties as that of hidden-charm pentaquarks system are obtained.

Comments: 10 pages, 4 figures