We developed a theoretical approach to elastic electron scattering on nuclei that includes a two-photon-exchange mechanism responsible for parity-conserving single-spin beam asymmetries. The two-photon-exchange amplitude at small scattering angles is treated in a diffractive framework similar to that used for pion-nucleus elastic scattering, and the approach is applied to the nuclei ${}_6^{12}\mathrm{C},{}_{20}^{40}\mathrm{Ca}$, and ${}_{82}^{208}\mathrm{Pb}$. The predicted kinematic features of the beam polarization asymmetries for different nuclei may reconcile Jefferson Lab's experimental results at finite scattering angles with a forward limit given by an optical theorem, potentially resolving the so-called “PREX puzzle” for ${}_{82}{}^{208}\mathrm{Pb}$.

Close

PrevNext

View figure in article

• Elastic scattering reactions
• Lepton induced nuclear reactions
• Nuclear charge distribution
• Nuclear radii
• Polarization phenomena