Generation of narrow beams of ultrarelativistic positrons (electrons) in the resonant strong electromagnetic field-assisted Breit-Wheeler process

The resonant external field-assisted Breit-Wheeler process (Oleinik resonances) for strong electromagnetic fields with intensities less than the critical Schwinger field has been theoretically studied. The resonant kinematics has been studied in detail. The case of high-energy initial gamma quanta and emerging ultrarelativistic electron-positron pairs is studied. The resonant differential cross section is obtained. The generation of narrow beams of ultrarelativistic positrons (for Channel A) and electrons (for Channel B) is predicted with a probability significantly exceeding corresponding to the non-resonant process.