EFFECT OF THE 3-NUCLEON FORCE ON THE 3-NUCLEON GROUND-STATE - REDUCIBLE AND IRREDUCIBLE CONTRIBUTIONS

The Tucson-Melbourne two-pion exchange three-nucleon force is split into a reducible part mediated by DELTA-excitation and an irreducible part not mediated by DELTA-excitation. The triton binding energy is calculated. The irreducible part of the Tucson-Melbourne force is taken into account in the calculation. Its reducible part is discarded, but regenerated by the explicit treatment of the DELTA-isobar in a coupled-channel approach. The remaining irreducible part of the Tucson-Melbourne force makes a nonnegligible contribution to the triton binding energy. The strong dependence of the triton binding energy on the cutoff parameter for the pi-NN vertex in the Tucson-Melbourne force is considerably reduced.