Electromagnetic Parity Violation for Hadrons

It is argued that a first-order weak direct parity-violating electromagnetic interaction should exist for hadrons. The interaction vanishes for real photons if the initial and final hadrons are identical and if off-mass-shell effects are neglected; the interaction contributes to reactions where this is not the case or for virtual photons. Estimates of the magnitude of parity-violating effects are made for nuclear electromagnetic transitions and for electron-proton elastic scattering. It is shown that asymmetries ≈ ${10}^{-6\mathrm{}}$ - ${10}^{-5\mathrm{}}$ can be expected in 20-GeV elastic electron scattering from polarized protons.