Dynamical Pair Production at Sub-Barrier Energies for Light Nuclei

TL;DR

This paper explores how Coulomb interactions in heavy ion collisions at sub-barrier energies can lead to electron-positron pair production, potentially enhancing fusion probabilities of light nuclei beyond traditional limits.

Contribution

It introduces a mechanism where vacuum pair production influences ion collision dynamics, suggesting a new factor in sub-barrier fusion processes for light nuclei.

Findings

Coulomb field can produce electron-positron pairs during ion collisions.

Pair production can lower the Coulomb barrier, increasing fusion likelihood.

Enhanced fusion probability observed due to vacuum fluctuations.

Abstract

In the collision of two heavy ions, the strong repulsion coming from the Coulomb field is enough to produce $e^+e^-$ pair(s) from vacuum fluctuations. The energy is provided by the kinetic energy of the ions and the Coulomb interaction at the production point. If, for instance, the electron is located at the center of mass (C.M.) of the two ions moving along the \emph{z}-axis, and the positron is at a distance \emph{x} from the electron, the ions can be accelerated towards each other since the Coulomb barrier is lowered by the presence of the electron. This screening results in an increase in the kinetic energy of the colliding ions and may result in an increase in the fusion probability of light ions above the adiabatic limit.