Pair creation in heavy ion channeling

TL;DR

This paper explores how heavy ions channeling through crystals at multi-GeV energies can produce electron-positron pairs, with resonant enhancement when virtual photon energies match nuclear transitions, leading to high pair production rates.

Contribution

It introduces a novel two-step excitation-pair conversion mechanism that leverages crystal periodicity to significantly enhance pair production rates in heavy ion channeling.

Findings

Resonant enhancement occurs when virtual photon frequency matches nuclear transitions.

Pair production rates scale quadratically with the number of crystal sites.

High pair production rates are achievable at multi-GeV energies.

Abstract

Heavy ions channeling through crystals with multi-GeV kinetic energies can create electron-positron pairs. In the framework of the ion, the energy of virtual photons arising from the periodic crystal potential may exceed the threshold $2mc^2$. The repeated periodic collisions with the crystal ions yield high pair production rates. When the virtual photon frequency matches a nuclear transition in the ion, the production rate can be resonantly increased. In this two-step excitation-pair conversion scheme, the excitation rates are coherently enhanced, and they scale approximately quadratically with the number of crystal sites along the channel.