Another look at meson-exchange interactions

We calculate the nucleon structure in a two-phase model, assuming forlow Q ²: meson dynamics, and forhigh Q ²: quark-gluon dynamics, and find a low meson scale in accordance with electron-nucleon scattering. Using these form factors we show that with the increased importance of nucleon structure in the nucleon-nucleon interaction, higher-mass meson exchange (m>1 GeV) becomes important. We argue that these contributions can be taken into account by a sort of closure relation, leading to contact interactions of the physical nucleons. A one-boson-exchange potential is constructed including these direct nucleon structure interactions. Implications concerning the corresponding three-nucleon interaction are also discussed. A partial-wave calculation of neutron-proton scattering is performed showing satisfactory agreement with experiment. The model has several advantages over conventional bosonexchange models.Work is supported by Deutsche Forschungsgemeinschaft (Ga 153/11-2 and Ga 153/11-3) and partially by NATO (0581/87) and COSY-KFA Jülich (41092744 and 41116381)