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

Abstract

Measurements of the processes p(\ensuremath{\pi},\ensuremath{\pi}), p(\ensuremath{\nu},\ensuremath{\nu})/p(\ensuremath{\nu}\ifmmode\bar\else\textasciimacron\fi{},\ensuremath{\nu}\ifmmode\bar\else\textasciimacron\fi{}), and deep-inelastic p\ensuremath{\rightarrow}(\ensuremath{\mu}\ensuremath{\rightarrow},\ensuremath{\mu}') 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 $^{9}\mathrm{Be}$ and $^{12}\mathrm{C}$ are small, significant strange-quark contributions might be expected in experiments with nuclear targets at higher momentum transfer.