Comparison of results for $N+N$ scattering at low energies

We show comparisons of $N+N$ scattering observables calculated from the Nijmegen potential with those obtained from an $R$-matrix analysis of low-energy measurements for the $N+N$ system. Of particular interest are the spin-dependent $S$-wave scattering lengths for $n+p$ scattering, and selected observables (with their associated uncertainties) for $n+p$ capture. We will discuss implications of the comparisons for the nature of phenomenological $N-N$ interactions.