Annihilation of Relativistic Positrons in Single Crystal with production of One Photon

TL;DR

This paper explores how relativistic positrons can annihilate with electrons in a single crystal to produce a single photon, a process forbidden in vacuum but potentially enabled by the crystal's channeling effects.

Contribution

It introduces the possibility of single photon annihilation of positrons in a crystal due to channeling, expanding understanding of particle interactions in structured media.

Findings

Single photon annihilation is possible in a crystal with channeling.

Probability of single photon annihilation increases with channeling conditions.

The process differs fundamentally from vacuum annihilation due to crystal effects.

Abstract

The energy and momentum conservation laws prohibit positron-electron annihilation in vacuum producing the single photon only. It can produce two photons in vacuum, or the process is possible with a participation of the third body. 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 when the transverse motion of a particle is bound or sufficiently uneven. It may increase sharply the probability of the single photon annihilation process.