Quadrupole radiation and $e^+e^-$ pair production in the collision of nonrelativistic nuclei

TL;DR

This paper investigates the role of electric quadrupole radiation in electron-positron pair production during nonrelativistic nuclear collisions, highlighting its dominance over dipole radiation in many cases.

Contribution

It provides a detailed analysis of quadrupole radiation effects and compares them with dipole and two-photon mechanisms in nonrelativistic nuclear collisions.

Findings

Quadrupole radiation significantly contributes to pair production cross section.

Finite nuclear size effects are thoroughly examined.

Quadrupole contribution dominates over dipole in a wide velocity range.

Abstract

We analyze the one-photon mechanism of $e^+e^-$ pair production in the collision of nonrelativistic nuclei. The contribution of electric quadrupole radiation of virtual photon to the corresponding cross section is found. The effect of the finite nuclear size is considered in detail. A comparison is made with the contribution of electric dipole radiation of virtual photon and with the contribution of the two-photon pair production mechanism. It is shown that the contribution of electric quadrupole radiation is dominant in a wide range of relative velocities. The cross section for the production of $e^+e^-$ pair with the capture of an electron by one of the nuclei is also analyzed.