Parton Structure of the Nucleon and Precision Determination of the Weinberg Angle in Neutrino Scattering

A next-to-leading-order (NLO) calculation of neutrino cross sections, including power-suppressed mass terms, is used to evaluate the Paschos-Wolfenstein ratio, in order to better assess the validity and significance of the NuTeV anomaly. We study the shift of ${sin}^2{\theta }_{\mathrm{W}}$ obtained in calculations with parton distribution function sets that allow $s\left(x\right)\ne \bar{s}\left(x\right)$, enabled by recent neutrino dimuon data from CCFR and NuTeV. The extracted value of ${sin}^2{\theta }_{\mathrm{W}}$ is closely correlated with the strangeness asymmetry. Taken together with recent developments of possible isospin violation and electroweak effects, our results suggest that the new dimuon data, the Weinberg angle measurement, and other data sets used in global QCD parton structure analysis can all be consistent within the standard model. A full NLO analysis of the actual experimental measurement will help to clarify this issue further.