Study of $qqq\bar{q}Q$ pentaquark system in the Chiral Quark Model

Abstract

With the discovery of some hidden-charm pentaquark resonances by the LHCb Collaboration, investigations of pentaquark states containing heavy quarks have aroused the interest of theorists. We study herein $qqq\bar{q}Q$ ($q=u$ or $d$, $Q=c$ or $b$) pentaquark system, in the framework of the chiral quark model. In consequence, some charmed and bottomed pentaquarks are considered to exist by five-body dynamical calculations. In the charm sector, ${\Sigma }_c\pi (I{J}^P=0{\frac{1}{2}}^{-})$ and ${\Sigma }_c^{\ast }\pi (I{J}^P=0{\frac{3}{2}}^{-})$ are possible candidates of ${\Lambda }_c(2595)$ and ${\Lambda }_c(2625)$, respectively. Besides, two high-spin states, ${\Sigma }_c^{\ast }\rho (I{J}^P=0{\frac{5}{2}}^{-})$ and $\Delta D^{\ast }(I{J}^P=1{\frac{5}{2}}^{-})$, are also found in the energy region of $3.2\sim 3.3$ GeV. In the bottom sector, ${\Sigma }_b\pi (I{J}^P=0{\frac{1}{2}}^{-})$, ${\Sigma }_b^{\ast }\pi (I{J}^P=0{\frac{3}{2}}^{-})$ could be candidates of ${\Lambda }_b(5912)$ and ${\Lambda }_b(5920)$, respectively. And ${\Sigma }_b^{\ast }\rho (I{J}^P=0{\frac{5}{2}}^{-})$ and $\Delta B^{\ast }(I{J}^P=1{\frac{5}{2}}^{-})$ are found in the energy region of $6.5\sim 6.6$ GeV. ${\Sigma }_c^{(\ast )}\pi$ and ${\Sigma }_b^{(\ast )}\pi$ are expected as compact states, while ${\Sigma }_c^{\ast }\rho$, ${\Sigma }_b^{\ast }\rho$, $\Delta D^{\ast }$ and $\Delta B^{\ast }$ are expected as molecular states.

Comments: 11 pages, 1 figure