Topological solitons of the Nambu-Jona-Lasinio model

The baryon number one soliton solution of the Nambu-Jona-Lasinio model are found numerically in the mean-field approximation with full inclusion of the Dirac sea using the proper-time regularization for the underlying fermion determinant (quark loop). Explicit breaking of chiral symmetry is included by bare (current) quark masses. The obtained lowest-energy chiral soliton solutions with baryon number one carry winding number one. Fitting the parameters of the model from low-energy pion data the classical energies of these solitons are of the order of the nucleon mass. (orig.)