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 _cpi (IJ^P=0frac{1}{2}^-) and Sigma _c^*pi (IJ^P=0frac{3}{2}^-) are possible candidates of Lambda _c(2595) and Lambda _c(2625), respectively. Besides, two high-spin states, Sigma _c^*rho (IJ^P=0frac{5}{2}^-) and Delta D^*(IJ^P=1frac{5}{2}^-), are also found in the energy region of 3.2 sim 3.3 GeV. In the bottom sector, Sigma _bpi (IJ^P=0frac{1}{2}^-), Sigma _b^*pi (IJ^P=0frac{3}{2}^-) could be candidates of Lambda _b(5912) and Lambda _b(5920), respectively. And Sigma _b^*rho (IJ^P=0frac{5}{2}^-) and Delta B^*(IJ^P=1frac{5}{2}^-) are found in the energy region of 6.5 sim 6.6 GeV. Sigma _c^{(*)}pi and Sigma _b^{(*)}pi are expected as compact states, while Sigma _c^*rho , Sigma _b^*rho , Delta D^* and Delta B^* are expected as molecular states.