B = 1 SOLITON OF THE NAMBU-JONA-LASINIO MODEL IN MEDIUM

The solitonic sector of the Nambu-Jona-Lasinio model with baryon numbe r one is solved in the presence of an external medium. The calculation s fully include the polarization of both the Dirac sea and the medium as well as the Pauli-blocking effect. We found that with an increasing density the medium destabilizes the soliton. At finite medium density the soliton mass gets reduced whereas the mean-square baryon radius s hows an increase - a swelling of the soliton. At some critical density of about two times nuclear matter density there is no localized solut ion - the soliton disappears.