Polarization in nuclear excitation by electron impact

• Study of spin asymmetry in inelastic electron–nucleus scattering below 220 MeV.
• Large transverse spin asymmetry for strongly collective excitation of heavy nuclei.
• Quenching of transverse spin asymmetry by transverse electric and magnetic scattering.

Electron–electron polarization correlations from nuclear excitation by spin-polarized electrons are studied within the distorted-wave Born approximation. Restriction is made to spin-0 and to unpolarized spin-12 nuclei. When Coulomb scattering is dominant the resulting spin asymmetries may exceed those from elastic scattering. However, at the backmost scattering angles or for large transition current densities where magnetic scattering prevails, there is a strong suppression of the transverse polarization correlations. Predictions are made for the excitation of the lowest 3−3− and 5−5− states of 208Pb and the lowest 52− state of 89Y by 60–220 MeV electrons.