A Departure from prediction: Electroweak physics at NuTeV

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 antineutrino 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 {nu}N scattering experiments. Our null hypothesis test of the standard model prediction measures sin{sup 2} {theta}{sub W}{sup (on shell)} = 0.2277 {+-} 0.0013(stat) {+-} 0.0009(syst), a value which is 3.0{sigma} above the prediction. We discuss possible explanations for and implications of this discrepancy.