Vector and axial-vector meson dominance in neutrino scattering and the measurement of sin²θ_W

Contributions to neutrino scattering which are proportional to 1/Q² are estimated using vector and axial-vector meson dominance. They are found to be potentially larger than previous estimates of nonleading twist. They lead to an additional theoretical uncertainty, on the order of _-0.00^+0.01, in the value of sin²θ_W which is extracted from the neutrino cross-section ratio σ^NC/σ^CC. This suggests that the mass of the top quark is likely to lie near the lower end of its currently allowed range in the minimal standard model.