Precise Determination of Electroweak Parameters in Neutrino-Nucleon Scattering

Abstract

The NuTeV Collaboration has extracted the electroweak parameter ${sin}^{2}{\ensuremath{\theta}}_{W}$ from the measurement of the ratios of neutral current to charged current $\ensuremath{\nu}$ and $\overline{\ensuremath{\nu}}$ cross sections. Our value, ${sin}^{2}{\ensuremath{\theta}}_{W}^{(\mathrm{on}\ensuremath{-}\mathrm{shell})}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.2277\ifmmode\pm\else\textpm\fi{}0.0013(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.0009(\mathrm{syst})$, is 3 standard deviations above the standard model prediction. We also present a model independent analysis of the same data in terms of neutral-current quark couplings.