Strange quark asymmetry in the nucleon and the NuTeV anomaly

The NuTeV anomaly of a nonuniversal value of the fundamental parameter ${sin}^2{\theta }_W$ in the electroweak theory has been interpreted as an indication for new physics beyond the standard model. However, the observed quantity depends on a possible asymmetry in the momentum distributions of strange quarks and antiquarks in the nucleon. This asymmetry occurs naturally in a phenomenologically successful physical model for such parton distributions, which reduces the NuTeV result to only about 2 standard deviations from the standard model.