The CCFR collaboration reports a precise measurement of electroweak parameters derived from the ratio of neutral-current to charged-current cross-sections in neutrino-nucleon scattering at the Fermilab Tevatron. We determine sin~2 θ_W~((on-shell)) = 0.2236 ± 0.0028(expt.) ± 0.0030(model ) for M_(top) = 175 GeV, M_(Higgs) = 150 GeV. This is equivalent to M_W = 80.35 ± 0.21 GeV. The good agreement of this measurement with Standard Model expectations implies the exclusion of additional vvqq contact interactions at 95% confidence at a mass scale of 1-8 TeV, depending on the form of the contact interaction.
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