A Lane-model analysis of the ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$+nucleon system has provided a detailed description of both cross-section and polarization data for ($p$,$p$) elastic, ($n$,$n$) elastic, and ($p$,$n$) quasielastic scattering over a range of energies. Emphasis is placed on consistency in isospin conservation, data-set completeness, and multichannel constraints. Results favor a symmetry potential which is energy dependent with volume and surface form factors for the real and imaginary wells, respectively. A symmetry spin-orbit $\left(\overrightarrow{1}·\overrightarrow{\sigma }\right)\left(\overrightarrow{\mathrm{t}}·\overrightarrow{\mathrm{T}}\right)$ interaction was found to be unnecessary.

• Received 6 September 1978

DOI:https://doi.org/10.1103/PhysRevLett.43.260