The Sherman function in highly relativistic elastic electron–atom scattering

Abstract

The Sherman function, which is a measure of the spin asymmetry in the elastic scattering of transversely polarized electrons from heavy targets, is calculated within the relativistic partial-wave representation. For collision energies above 40 MeV, oscillations of the Sherman function develop at the backward scattering angles which mirror the influence of the nuclear potential and which scale inversely with the nuclear size. We give predictions for 20-200 MeV electrons colliding with 64 Zn, 208 Pb and 238 U. We propose the measurement of the diffraction structures in the angular distribution of the Sherman function for a 208 Pb target at a beam energy near 80 MeV. The feasibility of such an experiment is addressed.

e± Ar scattering in the energy range 1 eV ≤ E i ≤ 0.5 GeV

“…The phase shift analysis [55,56] remains the same as applied at the lower energies, using equations (27) and (28)for the calculation of f q ( ) and g(θ). However, for energies E i >1 MeV, the sum has to be carried out with the help of a multiple convergence acceleration [57].…”

The influence of vacuum polarization on the Sherman function during elastic electron-nucleus scattering

“…2a for 64 Zn) but, as seen from Fig. 3, they also modulate the vacuum-polarization induced changes of S. In particular, dS shows oscillations with E kin in the same way as does S(V T ) which is displayed in [17] for 208 Pb. It should be noted, however, that dS as defined by (9) largely overestimates the influene of vacuum polarization if the diffraction effects lead to a spin asymmetry which approaches zero or changes sign.…”

“…r→0 rU e (r) = 0. Numerical details are described in [17]. In calculating ψ V P we have disregarded any screening by the bound target electrons since such effects do not play a role at the high momentum transfers considered here.…”

“…The spin asymmetry S for electrons spin-polarized perpendicular to the scattering plane (defined by the momenta of incoming and outgoing electron) and scattering from an arbitrary potential V is defined as the relative cross section difference when the spin of the beam electron is flipped (see e.g. [1,17]),…”

Above-threshold ionization with highly charged ions in superstrong laser fields. III. Spin effects and their dependence on laser polarization

“…The photoelectron spin polarization can be measured using Mott polarimetry [83][84][85]. The latter is based on the left-right asymmetry of Mott scattering cross section on a high-κ target.…”