Unified study of nucleon and. baryon spectra and their strong decays with chiral dynamics

In this work, we systematically study both the mass spectra and strong decays of the nucleon and Delta resonances up to the N = 2 shell within a unified quark model framework with chiral dynamics. In this framework we achieve a good description of the strong decay properties of the well-established nucleon and Delta resonances. Meanwhile, the mass reversal between N(1440)1/2(+) as the first radial excitation state and the 1P-wave nucleon resonances can be explained. We show that the three-body spin-orbit potential arising from the one-gluon exchange can cause a large configuration mixing between N(1520)3/2(-) and N(1700)3/2(-) and is also responsible for the large splitting between Delta(1600)1/2(-) and Delta(1700)3/2(-). Some of these baryon resonances tend to weakly couple to the N pi, N eta, K Lambda, and K Sigma channels, which may answer the question of why they have not been established in these channels via the pi N and gamma N scatterings. It shows that these "missing resonances" may have large potentials to be established in the N pi pi final state due to their large decay rates into either the Delta(1232) or 1P-wave nucleon resonances via the pionic decays. Further experimental search for their signals in charmonium decays at BESIII is thus strongly recommended.