Unitary pole approximation andt-matrix perturbation theory in triton calculations
We find that the quality of the fits of the UPAt-matrix to the exactt-matrix for a given potential do not depend strongly on specific features, such as locality or inclusion of spin orbit forces in the potential. The accuracy of the UPA fits suggests the employment oft-matrix perturbation theory in triton ground state calculations. The accuracy of first ordert-matrix perturbation theory is satisfactory for the rank two separable tensor Tabakin potential.