Chiral bag model for the nucleon

We review the chiral bag model for the nucleon at low energy. The model is a hybrid model of quark and meson degrees of freedom, interpolating the two limits of the Skyrme model at R --> 0 and the MIT bag model at R --> infinity, where R is the bag radius. Baryon number one (B = 1) solutions are obtained in the semiclassical method, where the nucleon is regarded as a slowly rotating hedgehog. We investigate static properties of the nucleon such as masses and magnetic moments as functions of R, first in the original chiral bag model and second in the models with vector mesons. We find a reasonably good description for the nucleon in both cases at an intermediate bag radius R similar to 0.6 fm. Results of the model calculations are then re-derived using a group theoretical method in the large-N-c limit.