Eur. Phys. J. D (2017) 71: 209
https://doi.org/10.1140/epjd/e2017-80056-3

Regular Article

Validity of sum rules for the polarization transfer in electron bremsstrahlung

Mathematics Institute, University of Munich, Theresienstrasse 39, 80333 Munich, Germany

^a e-mail: dj@mathematik.uni-muenchen.de

Received: 27 January 2017
Published online: 8 August 2017

Abstract

The polarization correlations, which describe the spin transfer from a high-energy spin-polarized electron to the photon in the elementary process of bremsstrahlung induced by strong potentials, obey a strict sum rule in the case of coplanar emission. The proof is carried out within the relativistic partial-wave approach. Further sum estimates are obtained by means of a variational principle under the sole condition that the transition amplitude is linear in the electron wavefunctions and in the photon field. Numerical sum rule results are given for light and heavy bare target atoms in the energy range 1–10 MeV.