Nuclear forces within a consistent meson-exchange model

Abstract

In this contribution we present a meson-exchange model for the NN-interaction which includes irreducible diagrams up to fourth order in a consistent way. These diagrams contain in particular an explicit determination of the 2π-exchange taking into account virtual 4-excitation and direct ππ-interaction. This part of the model agrees quantitatively with results obtained from dispersion theory which in turn are based on the analysis of πN- and ππ-scattering data. A detailed interpretation of the lower partial wave phase-shifts of NN-scattering requires, however, (apart from the well-known OBE contributions) the introduction of additional irreducible diagrams containing also heavy boson exchange, in particular the combination of π and p. In the framework of this consistently extended meson model (it contains all terms up to an exchanged mass of 1 GeV) an accurate description of the NN-scattering data below 300 MeV laboratory energy as well as the deuteron data is achieved; the numerical results are definitely superior to well-known simplified boson exchange models, e.g. the one-boson exchange. Our enlarged viewpoint has also important consequences within the theory of nuclear matter due to our explicit determination of the 2π-exchange.