HEAVY-QUARK SOLITONS IN THE NAMBU-JONA-LASINIO MODEL

The Nambu-Jona-Lasinio (NJL) model is extended to incorporate heavy qu ark spin symmetry. In this model baryons containing one heavy quark ar e analyzed as bound states of light baryons, represented as chiral sol itons, and mesons containing one heavy quark. From related studies in Skyrme-type models, the ground-state heavy baryon is known to arise fo r the heavy meson in a P-wave configuration. In the limit of an infini tely large quark mass the heavy meson wave function is sharply peaked at the center of the chiral soliton. Therefore, the bound state equati on reduces to an eigenvalue problem for the coefficients of the operat ors contained in the most general P-wave ansatz for the heavy meson. W ithin the NJL model a novel feature arises from the coupling of the he avy meson to the various light quark states. In this respect conceptua l differences to Skyrme-model calculations are discovered: The stronge st bound state is given by a heavy meson configuration, which is compl etely decoupled from the grand spin zero channel of the light quarks.