A comparison of angular behaviors among electron and positron scattering factors

In this review, we discuss the angular anisotropies in the scattering facto rs of electrons and positrons for scattering by atoms in solids. We show th at, as a function of the angle, the maximum number of dips in the scatterin g factor's magnitude and jumps of near pi in its phase are related to the a ngular momenta of the bound and resonance states of the potential. The effe ct of the scattering factor's anisotropies on low-energy electron and posit ron holographic wave-front reconstruction is discussed.