Strange-quark vector currents and parity-violating electron scattering from the nucleon and from nuclei

Measurements of the processes p(π,π), p(ν,ν)/p(ν¯,ν¯), and deep-inelastic p→(μ→,μ') can be interpreted in a manner which requires a significant strange-quark contribution to proton matrix elements. In this paper some implications of strange-quark contributions to proton vector currents and their manifestation in parity-violating electron-scattering experiments are examined. It is found that strange-quark currents of plausible magnitude significantly affect the parity-violating elastic electron scattering from the nucleon in certain kinematic regimes. It is also shown that, while the effects in on-going parity-violating experiments on 9Be and 12C are small, significant strange-quark contributions might be expected in experiments with nuclear targets at higher momentum transfer.