Annihilation of relativistic positrons in single crystal with production of one photon

Abstract

The energy and momentum conservation laws prohibit positron–electron single-photon annihilation in vacuum. It is shown that the situation is different in a single crystal with one of the leptons (e.g. positron) moving in the channeling (or in the quasi-channeling) mode. The transverse motion of an oriented or channeled particle may sharply increase the probability of the single-photon annihilation process.

The Single-Photon Annihilation of Channeled Positron in Si Crystal

“…A detailed study of orientation dependence is planned to be carried out in a separate work. Overall, the results of our calculations confirm the qualitative conclusion of [39] about the orientation dependence of the process under study.…”

“…As far as we know there is only one work devoted to the theoretical consideration of SPA of a channeled positron on the K-electron of an atom of crystal [39].…”

“…In the paper [39], based on a qualitative analysis of the populations of transverse quantum states of a channeled positron it was studied the dependence of the cross-section on the angle between positron momentum and crystal plane. It was concluded for a positron with energy 25 MeV channeled in (110) Si that with increasing of the entry angle of the positron into the crystal the differential cross-section increase.…”