A Precise measurement of the weak mixing angle in neutrino - nucleon scattering

This dissertation reports a precise determination of the weak mixing angle, sin 2 &thetas;W, from measurement of the ratios of neutral current to charged current neutrino deep inelastic cross sections. High statistics samples of separately collected neutrino and antineutrino events, resulting from exposure to the Fermilab neutrino beam during the period from 1996 to 1997, allowed the reduction of systematic errors associated with charm production and other sources. The final value, sin 2 &thetas;W (on shell) = 0.2277 ± 0.0013 (stat) ± 0.0009 (syst), lies three standard deviations above the standard model prediction. The measurement is currently the most precise determination of sin 2 &thetas; W in neutrino- nucleon scattering, surpassing its predecessors by a factor of two in precision. A model independent analysis recasts the same data into a measurement of effective left and right handed neutral current quark couplings.