Parity Violating Electron Scattering

We report on a mature experimental program to measure the parity violating asymmetry in the elastic scattering of longitudinally polarized electrons from unpolarized 1H, 2H, 4He and 208Pb targets. One focus is the measurement of the nucleon neutral weak form factors at intermediate four-momentum transfer (0.1 < Q2 < 1) (GeV/c)2 which provide information about the impact of virtual strange quarks on the charge and current distributions inside nucleons. Another focus is the neutral current elastic amplitude at very low Q2, which can provide stringent tests of the standard model and possess unique sensitivity to new physics at the TeV scale. Finally, the elastic neutral weak amplitude from scattering off a heavy spinless nucleus is very sensitive to the presence of a neutron skin. We report on recent technical progress in the design and scope of the experimental techniques. The physics implications of the published measurements are discussed and the current status and anticipated results experiments under construction are summarized