Solution of the Faddeev-Yakubovsky equations using realistic NN and 3N interactions

We solve the Faddeev-Yakubovsky equations for 3N and 4N bound states based on the most modern realistic nucleon-nucleon interactions. We include diffe rent realistic 3N forces. It is shown that all 3N force models can remove t he underbinding of the triton and alpha -particle which one obtains with ex isting NN interactions. The agreement of theoretical predictions and the ex perimental binding energy is quite good and there is little room left for t he action of four-nucleon forces in the a-particle. The effect of 3N forces on the wave function is investigated.