Quark model estimate of hidden-charm pentaquark resonances

A quark model, which reproduces the ground-state mesons and baryons, i.e., the threshold energies, is applied to the qqqcc configurations, where q is a light quark and c the charmed quark. In the calculation, several open channels are explicitly included such as J/ψ+N, ηc+N, Λc+D, etc. To distinguish genuine resonances and estimate their width, we employ the Gaussian expansion method supplemented by the real scaling method (stabilization). No resonance is found at the energies of the Pc(4380) and Pc(4450) pentaquarks. On the other hand, there is a sharp resonant state at 4690 MeV with a J=1/2- state and another one at 4920 MeV with a J=3/2- state which have a compact structure.