Finite-Range Delta-Function Potential

The long-range part of the nucleon-nucleon potential is approximated by the finite-range delta-function potential: $V_{\mathrm{singlet}\mathrm{even}}=V_1\delta \mathrm{}(r-a)\mathrm{}$, $V_{\mathrm{triplet}\mathrm{even}}=V_3\delta \mathrm{}(r-a)+V_T\delta \mathrm{}(r-a)\mathrm{}{S}_{12}$. The best fit to the low-energy $n-p$ data is obtained when $V_3$ is repulsive and $V_T$ is large. The uncertainties in the $V\text{'}\mathrm{s}$ are of the order of 10%.