Determination of electroweak parameters from the elastic scattering of muon neutrinos and antineutrinos on electrons

Total and differential cross sections for ν_μe→ν_μe and ν_μe→ν_μe are measured. Values for the model-independent neutral-current couplings of the electron are found to be gV=-0.107±0.035(stat)±0.028(syst) and gA=-0.514±0.023(stat)±0.028(syst). The electroweak mixing parameter sin²θW is determined to be 0.195±{}0.018(stat)±{}0.013(syst). Limits are set for the charge radius and magnetic moment of the neutrino as (〈r²〉)<0.24×10^-32 cm² and f_μ<0.85×10^-9 Bohr magnetons, respectively.