Positronia' clouds in Universe

TL;DR

This paper explores how electromagnetic interactions in high-energy nuclear collisions can produce low-mass electron-positron pairs, potentially explaining observed 511 keV photon emissions in the universe and terrestrial phenomena.

Contribution

It introduces a novel mechanism for positronium cloud formation via electromagnetic fields in heavy ion collisions, emphasizing the role of low-mass pair production and Coulomb attraction effects.

Findings

Production cross sections increase with energy, potentially surpassing strong interaction cross sections.

Low-mass electron-positron pairs are significantly enhanced by the SGS factor.

The mechanism may explain astrophysical and terrestrial 511 keV photon sources.

Abstract

The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia' clouds. Unbound electron-positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favours abundant creation of the unbound electron-positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z$^4$ (Z is the electric charge of a heavy ion) compared to protons with Z=1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass $e^+e^-$-pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA collider.