Using an approximate Bethe-Salpeter equation approximate values were obtained for the partial wave contributions of the two and three pion exchange ladder diagrams. With these results the region hypothesis of the two-nucleon force was tested for this model. No definite region structure was observed for the $S$ and part of the $P$ and $D$ waves (${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}D_1^{}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}D_3^{}{}_{}{}^{}$). A definite region structure was observed for other waves, but it was impossible to locate common (to all partial waves) radii for the outer and intermediate regions of this model of the two-nucleon interaction.

• Received 6 May 1974

DOI:https://doi.org/10.1103/PhysRevC.10.1640