Off the Mass Shell: Electroweak Physics at NuTeV

TL;DR

The NuTeV experiment measured electroweak parameters with high precision using neutrino scattering, finding a significant deviation from the Standard Model prediction, which could imply new physics or systematic effects.

Contribution

This work provides the most precise electroweak measurements from neutrino scattering to date, revealing a 3-sigma discrepancy with the Standard Model prediction.

Findings

Measured sin^2θ_W = 0.2277 ± 0.0013 (stat) ± 0.0009 (syst)

Observed a 3-sigma deviation from the Standard Model prediction

Discussed potential explanations for the discrepancy

Abstract

The NuTeV collaboration 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 sigma above the prediction. We discuss possible explanations for and implications of this discrepancy.