Tensor-Force, Hard-Core, and Three-Body Parameters

Results are presented for the binding energy of ${\mathrm{H}}^3$ and the doublet $n-d$ scattering length ($a_{\frac{1}{2}}$) using a rank-four separable potential which simulates the hard core as well as the tensor force. The binding energy is nearly four times the deuteron binding energy, and $a_{\frac{1}{2}}$ is 0.13-0.18 F for the best available ${}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ potentials, in close agreement with the latest experimental value.