Positron annihilation in hydrogen-like ions

Abstract

Diagrammatic many-body perturbation theory is used to calculate the scattering phase shifts, annihilation rate parameters Zeff and γ-spectra for positrons annihilating on hydrogen-like ions. The enhancement of the annihilation probability above the independent-particle approximation is found to be almost entirely due to corrections to the annihilation vertex that describe electron-positron attraction at short range.