Electron-positron pair creation by Coulomb and laser fields in the tunneling regime

TL;DR

This paper analytically investigates electron-positron pair creation in combined Coulomb and laser fields within the tunneling regime, revealing detailed energy spectra and angular distributions influenced by laser polarization.

Contribution

It introduces the first analytical derivation of energy and angular distributions of pairs in this regime and proposes a new vicinal approximation method for calculation.

Findings

Energy spectra show a sharp maximum above the threshold.

Angular distributions depend on laser polarization.

Total pair creation rates match previous results.

Abstract

Electron-positron pair creation due to combined nuclear Coulomb and strong laser fields is investigated for the tunneling regime. The energy spectra and angular distributions of the pair are found analytically for the first time. The energy spectrum for each lepton exhibits a sharp maximum located well above the threshold for any polarization of the laser field. The angular distributions of leptons depend on the polarization: for the linear polarization both leptons move predominantly along the laser beam direction; for the circular polarization leptons are emitted in a thin-walled cone centered on the laser beam. The spectral and angular distributions found are governed by the intensity and frequency of the field, and the frequency independent total pair creation rates comply with the previously known results. A new method of calculation - the vicinal approximation - which uses the fact that the pair production takes place in the close vicinity of the nucleus, is suggested.