Scattering of Polarized Dirac Particles on Electrons

Abstract

The cross section for electron-electron scattering in which the incident and target electrons have arbitrary spin orientations has been evaluated. For the special case in which the spin of the incident electron is polarized along the direction of motion, two different spin effects are obtained. The first of these effects is simply a dependence of the cross section on the relative spin orientation; the second effect corresponds to an up-down asymmetry in the cross section. Similar effects have been obtained for the scattering of polarized positrons on polarized electrons.The depolarization of electrons and muons in scattering on unpolarized electrons also has been considered. For electrons which lose an appreciable fraction of their initial energy in passing through matter, the depolarization is appreciable. If the fractional energy loss is small the depolarization is proportional to the fractional energy loss. For nonrelativistic muons the depolarization which occurs as they are brought to rest in matter is found to be negligible.