Bremsstrahlung and pair production processes at low energies: Multidifferential cross section and polarization phenomena

Radiative electron-proton scattering is studied in peripheral kinematics, where the scattered electron and photon move close to the direction of the initial electron. Even in the case of an unpolarized initial electron, the photon may have a definite polarization. The differential cross sections with longitudinally or transversity polarized initial electrons are calculated. The relevant effective degrees of polarization are explicitly derived. The same phenomena are considered for the production of an electron-positron pair by a photon, where the final positron (electron) can be also polarized. Differential distributions for the case of a polarized initial photon are given. We extend the results obtained for protons to atoms of any atomic number, including screening.