Elastic Neutron-Alpha Scattering Analyses

An energy-dependent phase-shift analysis of 0-20-MeV $n-\alpha$ scattering is attempted. Reasonable fits to the 0-16.4 data are obtained, but the rest of the data up to 20 MeV elude good fits. Single-energy analyses at energies where polarization data are available corroborate the energy-dependent analysis. Our results differe from the Hoop-Barschall phases as follows: $P_{\frac{1}{2}}$ is larger between 3 and 10 MeV; $S_{\frac{1}{2}}$ and $P_{\frac{3}{2}}$ are larger between 10 and 16.4 MeV. We are not able to reliably determine $D$ or $F$ waves in this energy range.