Electron-positron pair production by photons in nonuniform strong fields

Area of Science:

• Quantum electrodynamics
• High-energy physics
• Particle physics

Background:

• Electron-positron pair production is a fundamental process in quantum electrodynamics.
• Previous models primarily focused on uniform electromagnetic fields.
• Understanding pair production in nonuniform fields is crucial for advanced physics applications.

Purpose of the Study:

• To develop a theoretical framework for calculating electron-positron pair production probability in strong, nonuniform electromagnetic fields.
• To introduce a new parameter characterizing field nonuniformity and its impact on pair production.
• To extend the applicability of pair production theories to weaker external fields.

Main Methods:

• Application of a model trajectory method within a semiclassical approach.
• Derivation of pair production probability using a novel invariant parameter, nu.
• Comparison of the derived formula with uniform-field approximations and the Bethe-Heitler formula.

Main Results:

• A new invariant parameter, nu, is introduced to quantify field nonuniformity.
• The derived formula accurately describes pair production across different nonuniformity regimes (nu>>1 and nu<<1).
• The theory predicts significant pair production in external fields too weak for uniform-field approximations.

Conclusions:

• The developed semiclassical theory provides a more comprehensive description of photon-induced pair production.
• The new parameter nu is essential for understanding pair production in realistic, nonuniform fields.
• The findings have implications for experiments involving crystal-assisted pair production and other high-field phenomena.