Mesonic and isobaric degrees of freedom in light nuclei

A study is made in 16O of the effects of mesonic and isobar degrees of freedom and the effect of the eikonal form factor in the meson-nucleon vertex of the nucleon-nucleon interaction. Three main effects are seen: First, the mesonic degrees of freedom introduce an additional density dependence of the interaction which results in a large improvement of the radius with a small change in the energy for 16O. Second, with inclusion of isobar degrees of freedom, repulsion is obtained in 16O with a corresponding increase of the radius. Third, the use of the eikonal form factor, instead of the phenomenological ones of the dipole type, results in additional attraction. (author)