Baryon Resonances in a Constituent Quark Model

The role of pseudoscalar mesons in the dynamical properties of baryon resonances is examined by means of the constituent quark model with meson-quark coupling. Since resonance properties are closely related to meson-baryon scatterings, it is important to include reaction processes as well as mass spectra in the analysis. The isobar model is employed to properly extract information of baryon resonances from reaction amplitudes. Prominent features of resonance spectra are reproduced fairly well by taking account of baryon self-energies due to meson-quark coupling. Several problems remained in the static quark model of baryons, e.g. Λ(1405)-Λ(1520) mass difference, are also studied. Brief comments on some improvements of the present model are given.