ELECTROWEAK PARAMETERS FROM A HIGH STATISTICS NEUTRINO NUCLEON-SCATTERING EXPERIMENT

The final results from the WA 1/2 neutrino experiment in the 1984 CERN 160 GeV narrow band beam are presented. The ratios Rν and {Mathematical expression} of neutral to charged current interaction rates of neutrinos and antineutrinos in iron are measured to be Rν=0.3072±0.0033 and {Mathematical expression}=0.382±0.016. A value of the electroweak parameter sin2 θw = 1 -mW2/mZ2 is extracted from Rν. The result is sin2 θw =0.228+0.013(mc-1.5)±0.0003 (theor.) where mc is the mass of the charmed quark in GeV for mt=60 GeV, MH=100 GeV, ρ=1. Combining Rν and {Mathematical expression} one obtains a value for ρ=0.991+0.023(mc-1.5)±0.020(exp.). Alternatively, Rν and {Mathematical expression} yield a precise value of the ratio of intermediate vector boson masses mW/mZ=0.880-0.007(mc-1.5)±0.002(exp.)±0.002(theor.). Comparison of these results with those from direct measurements of the vector boson masses are presented. In a model-independent analysis the left- and right-handed neutral current coupling constants, gL2 and gR2, are determined. © 1990 Springer-Verlag.