Multi-channel Interference in Nonperturbative Multiphoton Pair Production by Gamma Rays Colliding

TL;DR

This paper investigates nonperturbative electron-positron pair production by colliding intense gamma-ray lasers, revealing multi-channel interference effects, energy gaps, and testing the effective mass concept through detailed momentum spectrum analysis.

Contribution

It introduces a comprehensive three-dimensional computational analysis beyond the dipole approximation, uncovering multi-channel interference and nonperturbative features in pair production.

Findings

Direct observation of multi-photon pair production channels

Identification of energy gaps caused by Kapitza-Dirac scattering

Revelation of pair production suppression due to interference effects

Abstract

The electron-positron pair production in the collision of two intense gamma lasers is studied beyond the dipole approximation. The complete electron/positron momentum spectrum obtained by three-dimensional computation shows directly the multi-photon pair production channels and provides a sensitive test on the widely-used concept of the effective mass. Nonperturbative features are identified in the dependence of the total yield on the field intensity. In particular, various breaks in the momentum rings are observed and proved to be a manifestation of particle's energy gaps in the standing light wave induced by the Kapitza-Dirac scattering. A theoretical model of multi-level systems coupled by the Kapitza-Dirac scattering and pair production channels is established. Multi-channel interference effects and pair production suppression are revealed in these systems.