Parity violation in light atoms and the strange spin content of the proton

We re-evaluate standard model predictions for nuclear spin-dependent parity-violating effects in hydrogen and deuterium, in the light of the recent EMC measurement of polarized muon-proton scattering. This yields a new estimate of the isoscalar axial Z0 coupling to hadrons, whose compatibility with νN → νπN cross-section data we discuss. The EMC data indicate that, contrary to previous analyses, nuclear spin-dependent parity violation in deuterium is not dominated by electroweak radiative corrections, but rather by polarized strange quarks in the nucleon. (orig.)