High-accuracy comparison of electron and positron scattering from nuclei

We compare the elastic-scattering cross sections for electrons and positrons from ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. The results demonstrate that the electron-nucleus interaction can be described to good accuracy as a single hard-photon exchange process, and validate the theoretical framework used to interpret electron-scattering data in terms of ground-state charge densities of nuclei.