A precise determination of the electroweak mixing angle from semi-leptonic neutrino scattering

Abstract The cross section ratio of neutral-current and charged-current semi-leptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result: R v =0.3093±0.0031 for hadronic energy larger than 4 GeV. From this ratio, the electroweak mixing angle is determined to be sin 2 θ w =0.236+0.012( m c −1.5)±0.005 (exp.)±0.003 (theor.), where m c is the charm-quark mass in GeV/ c 2 .