Resonant Production of an Ultrarelativistic Electron–Positron Pair at the Gamma Quantum Scattering by a Field of the X-ray Pulsar

Abstract

The process of a resonant production of an ultrarelativistic electron–positron pair in the process of gamma-quantum scattering in the X-ray field of a pulsar is theoretically studied. This process has two reaction channels. Under resonant conditions, an intermediate electron (for a channel A) or a positron (for a channel B) enters the mass shell. As a result, the initial second-order process of the fine-structure constant in the X-ray field effectively splits into two first-order processes: the X-ray field-stimulated Breit–Wheeler process and the the X-ray field-stimulated Compton effect on an intermediate electron or a positron. The resonant kinematics of the process is studied in detail. It is shown that for the initial gamma quantum there is a threshold energy, which for the X-ray photon energy (1–102) keV has the order of magnitude (103–10) MeV. In this case, all the final particles (electron, positron, and final gamma quantum) fly in a narrow cone along the direction of the initial gamma quantum momentum. It is important to note that the energies of the electron–positron pair and the final gamma quantum depend significantly on their outgoing angles. The obtained resonant probability significantly exceeds the non-resonant one. The obtained results can be used to explain the spectrum of positrons near pulsars.

Advances in QED with intense background fields

“…Thus, the exchange term is important in order to answer this fundamental question. This discussion also applies to nonlinear double Compton scattering (e − → e − γγ) [311,303,203] and photon trident (γ → e − e + γ) [312,313] (resonance conditions for photon trident have been studied for weak fields in [314]). For double Compton scattering there are two diagrams because the two emitted photons are identical, and for photon trident there are two diagrams because the final photon can be emitted by either the electron or the positron.…”

Advances in QED with intense background fields

“…Thus, the exchange term is important in order to answer this fundamental question. This discussion also applies to nonlinear double Compton scattering (e − → e − γ γ ) [213,313,320] and photon trident (γ → e − e + γ ) [321,322] (resonance conditions for photon trident have been studied for weak fields in [323]). For double Compton scattering there are two diagrams because the two emitted photons are identical, and for photon trident there are two diagrams because the final photon can be emitted by either the electron or the positron.…”

Emission of high-energy gamma quanta by ultrarelativistic electrons on nuclei in strong x-ray fields

“…Astroparticle physics has been attracting attention for a long time (see, for example, articles [1][2][3][4]). At the same time, the processes of quantum electrodynamics (QED) in X-ray fields near pulsars and magnetars are intensively studied [5][6][7][8][9][10]. We also note a fairly large number of articles on QED processes in strong electromagnetic fields (see, for example, articles , reviews [44][45][46][47][48][49] and monographs [50][51][52]).…”