Paper detail

A two-pion exchange three-nucleon force based on a realistic pi-N interaction

The contribution of a $ππ$-exchange three-body force to the three-nucleon binding energy is calculated in terms of a $πN$ amplitude. The latter is based on a meson-theoretical model of $πN$ interaction developed by the Jülich group. Similar to a previous study based on simple phenomenological $πN$ potentials a very small effect of the resulting three-body force is found. Possible origins of the two-orders-of-magnitude descrepancy between the present result and the values obtained for the Tucson-Melbourne three-body force are investigated. Evidence is provided that this discrepancy is most likely due to strikingly different off-shell properties of the $πN$ amplitudes underlying the two approaches.