Polarized-electron-nucleon scattering in gauge theories of weak and electromagnetic interactions

The asymmetry in the scattering of longitudinally polarized electrons by nucleons is considered in the context of gauge theories of the weak and electromagnetic interactions. The predictions of a variety of gauge groups and assignments of fermion representations of present interest are given for deep-inelastic scattering, elastic scattering, and Δ electroproduction. It is shown that a combination of the three experiments carried out to a few parts in 10⁵ at Q²~1 GeV²/c² can distinguish between various SU(2) ×{} U(1) models and between various classes of models based on larger gauge groups.