Elastic Scattering of Protons by ${\mathrm{Fe}}^{56}$, ${\mathrm{Fe}}^{58}$, and ${\mathrm{Ni}}^{58}$ at 10.9 and 11.7 MeV

Differential cross sections for elastic scattering of protons from ${\mathrm{Fe}}^{56}$, ${\mathrm{Fe}}^{58}$, and ${\mathrm{Ni}}^{58}$ were measured and compared. Differences in positions of the maxima and minima are observed; when compared with the results of extensive optical model analyses of other data these are shown to be consistent with a nuclear symmetry dependence of the real nuclear-potential well depth. A comparison of the $A=58\mathrm{}$ data with previously reported $A=64\mathrm{}$ data shows the positions of maxima and minima in the differential elastic-scattering cross sections to be much more sensitive to differences of $\frac{\mathrm{}(N-Z)\mathrm{}}{A}$ than to differences in nuclear deformation.