The process of recombination of a quasifree electron into a bound state of an initially bare nucleus with the simultaneous creation of a bound-electron–free-positron pair is investigated. This process is called negative-continuum-assisted dielectronic recombination (NCDR). In a typical experimental setup, the initial electron is not free but bound in a light atomic target. In the present work, we study the effects of the atomic target on the single- and double-differential cross sections of positron production in the NCDR process. Calculations are performed within the relativistic framework based on QED theory, accounting for the electron-electron interaction to first order in perturbation theory. We demonstrate how the momentum distribution of the target electrons removes the nonphysical singularity of the differential cross section which occurs for the initially free and monochromatic electrons.

• Received 1 September 2015

DOI:https://doi.org/10.1103/PhysRevA.92.042708