Optical Potential from Dynamic Analysis of Elastic Electron-Nucleus Scattering

Dispersion effects in the analysis of high-energy electron-nucleus scattering lower the cross section obtained from a partial-wave analysis in its minima. At an electron energy $E=750\mathrm{}$ MeV and momentum transfer $q=3.9\mathrm{}$ ${\mathrm{fm}}^{-1\mathrm{}}$ the correction amounts to about 70% for ${\mathrm{Ca}}^{40}$. These dispersion effects may be described by an optical potential whose real part is determined by the usual static charge distribution, while the small imaginary part peaks at the nuclear surface with a maximum value of about 20 keV.