Dispersion corrections to elastic electron–nucleus scattering

Abstract

Calculations of the elastic scattering of polarized and unpolarized electrons from spin-zero nuclei within the recoil-modified phase-shift analysis are supplemented with the dispersion correction estimated within the second-order Born approximation. For the ^{12}C nucleus, three strong transient nuclear excitations are taken into account, for which not only Coulombic, but also magnetic transitions are considered. Dispersion effects of up to 10% in the differential cross section near the first diffraction minimum, resulting largely from Coulombic transitions at the higher collision energies, are in qualitative agreement with experimental findings. Below 300 MeV, dispersion is greatly influenced by magnetic scattering. Investigations of the spin asymmetry for perpendicularly polarized electrons indicate that it is strongly affected by dispersion, predominantly at small scattering angles.