Meson exchange contributions to the nucleon mass in the Faddeev approach to the NJL model

The effects of meson exchanges between quarks on the mass of the nucleonic solution of the relativistic Faddeev equation are perturbatively studied in the NJL model. It is found that the sigma meson exchange gives only a weak attraction, while the attraction due to the pion exchange reduces the nucleon mass by about 150 to 300 MeV.