Photon emission and electron-positron photoproduction processes in the planar field of a bent single crystal

The process of photon emission by a high-energy electron or positron moving in a bent single crystal with a constant curvature is considered. The relations for differential energy losses of particles and polarization of emitted photons are obtained. Corrections due to multiphoton production are found. The comparison of calculations with existing experimental data is carried out. The process of photoproduction of electron-positron pairs in a bent single crystal is also studied. The differential probabilities of the process taking into account the photon polarization are presented. Equations are obtained which determine the variation of the Stokes parameters of γ quanta, and their solutions are given.