Circular polarization of bremsstrahlung from high energy electrons with arbitrary polarization

Abstract

In view of the recently discovered possibilities of producing polarized electrons in parity-violating weak interactions --- BETA decay and mu -meson decay --- circular polarization of bremsstrahlung becomes of interest as a means for detecting the polarization. The bremsstrahlung circular polarization is found to be sensitive to transverse polarization; thus at high energies, E1 >> mc2, where Coulomb scattering is no longer feasible, it offers another possibility for detecting transverse electron spins. The Born approximation differential cross section was derived, and a summation over flnal electron spins and integration over final electron momenta were performed, with a result feasible for experimental application. The following general results were found: (1) bremsstrahlung is both linearly and circularly polarized; (2) the linear polarization is independent of any polarization of the initial electron; (3) circular pelarization occurs only for polarized initial electrons, (4) if this circular polarization is not observed, the radiation has the same angular distribution and spectrum as that from unpolarized electrons.