  The NuTeV experiment has performed precision measurements of the ratio of
neutral-current to charged-current cross-sections in high rate, high energy
neutrino and anti-neutrino beams on a dense, primarily steel, target. The
separate neutrino and anti-neutrino beams, high statistics, and improved
control of other experimental systematics, allow the determination of
electroweak parameters with significantly greater precision than past
neutrino-nucleon scattering experiments. Our null hypothesis test of the
standard model prediction measures
sin2thetaW=0.2277+/-0.0013(stat)+/-0.0009(syst), a value which is 3.0 standard
deviations above the prediction. We discuss possible explanations for and
implications of this discrepancy.
