These models are fairly successful at fitting the masses and static properties of baryons, with the masses usually identified with the bound state energies of quarks within some potential well. This means that the meson-baryon interactions do not directly affect the values of the baryon masses, and that the baryons are stable since decay channels are not coupled in. These experimental masses naturally include mass shifts due to the meson-baryon interactions as well as widths due to the coupling to the open channels. For this reason the bound-state energies of quarks bound in a potential well may not be realistic predictions of the experimental masses, and the dressed theories described in this proposal are needed. In our research we determine the masses and widths of excited baryons by calculating the meson-baron T matrix for a given model, and then finding the complex energies at which the scattering matrix has poles.
Bag models suffer from several limitations.
First, the use of an artificial bag to confine quarks leads to wave functions which have sharp discontinuities at the bag boundary. This leads to meson-baryon form factors and potentials containing unphysical oscillations and, presumably, limited ability to describe the scattering data. In addition, bag calculations treat the bare baryon masses and the bag radius as independent parameters even though we know this is not correct since for massless quarks the baryon masses are inversely proportional to the bag radius. The color dielectric field takes into account the long distance behavior of the QCD vacuum and produces a natural confinement of the quarks within baryons. In some recent CDM models, chiral symmetry is restored via a nonlinear realization which introduces an elementary pion field as a Goldstone boson.