Interpretations of the NuTeV $\sin^2 \theta_W$

Abstract

We summarize theoretical explanations of the three $\sigma$ discrepancy between $\sin^2 \theta_W$ measured by NuTeV and predicted by the Standard Model global fit. Possible new physics explanations ({\it e.g.} an unmized $Z'$) are not compelling. The discrepancy would be reduced by a positive momentum asymmetry $s^-$ in the strange sea; present experimental estimates of $s^-$ are unreliable or incomplete. Upgrading the NuTeV analysis to NLO would alleviate concerns that the discrepancy is a QCD effect.