QUARK-MESON COUPLING MODEL FOR BARYON WAVE-FUNCTIONS AND PROPERTIES

A scalar-isoscalar quark-meson interaction is used to mix fundamental pseudoscalar mesons directly into the wave functions of baryons. The parameters of the model are constrained using properties of the ground-state baryon spectrum, such as charge radii, strong decay widths, and the pion-nucleon coupling constant. Physical wave functions of the ground-state baryons are presented. With the physical wave functions, we calculate nucleon electric form factors and spin-32 baryon quadrupole moments. The addition of mesons produces effects on baryon properties comparable to effects due to spatial excitations of quarks. Although missing from most calculations, kaons and are found to be as important as pions in the baryon spectrum. Including mesons in the physical wave functions of baryons leads to the existence of low-energy resonances consisting primarily of three quarks in the ground state surrounded by a meson field. Most of these resonances decouple from the common production channels, but seven are expected to be observable. An additional N(12+) resonance state is calculated to have a mass close to that of the Roper resonance but a N width much smaller. A (32+) candidate state is calculated to have a mass and N width close to the experimental values for the (1600). © 1990 The American Physical Society.