Diquarks in a chiral soliton field

Abstract

In the Nambu--Jona-Lasinio model baryons are either considered as quark-diquark-composites or the soliton configurations of the model are interpreted as baryons. As a first step towards constructing a hybrid model, which possesses a dynamical interplay between both pictures, the Bethe-Salpeter equation for diquarks in the background of a soliton configuration is solved. The presence of the soliton causes a significant reduction of the resulting bound state eigenenergy of the diquark. As a consequence a unit baryon number configuration may be constructed with a mass lower than the energy of the soliton. An estimate of the influence of the diquark on the meson fields indicates a small decrease of the extension of the soliton due to diquark correlations.