A Precision Measurement of sin$^{2}\theta$$_{w}$ from Semileptonic Neutrino Scattering

There is considerable interest in measuring the electroweak mixing parameter sin$^{2}\Theta$$_{w}$, of the Glashow-Salam-Weinberg theory $^{1}$ as precisely as possible: first, its value may be predicted by models of Grand Unification;$^{2}$ second, precise measurements of sin$^{2}\Theta$$_{w}$ from different processes would test the validity of electroweak radiative corrections. $^{3,$}$. Different methods have been used to determine sin$^{2}\Theta$$_{w}$, over a large range of $Q^{2}$ values. FIGURE 1 gives a compilation of sin$^{2}\Theta$$_{w}$ with remarkable agreement between the results. At present, it is most precisely determined in semileptonic neutrino-nucleon scattering from the ratio of neutral current (NC) to charged current (CC) cross and in proton-antiproton collisions from the W boson mass. $^{10,11}$.