THE SOLITON OF THE NAMBU-JONA-LASINIO MODEL

The baryon number one soliton of the Nambu-Jona-Lasinio model is investigated numerically by a self-consistent procedure for various constituent masses using proper time regularization. Stable soliton solutions exist only for constituent masses higher than 400 MeV after the cutoff was fixed in order to reproduce the experimental value of the pion decay constant. The results for the axial coupling of the nucleon gA are almost constant over the considered range of constituent masses and are approximately fourty per cent lower than the experimental value. Additionally, an approximation is discussed which reproduces fairly accurately the properties of the fully self-consistent determined soliton profile witha greatly reduced numerical effort. © 1990.