Measurement of neutrino-proton and antineutrino-proton elastic scattering

We report here new measurements of neutrino-proton and antineutrino-proton elastic scattering, performed in the BNL neutrino beam. We observed a net signal of 212 neutrino events and 110 antineutrino events which lead to determination of the values R_ν≡σ(ν_μ+p-->ν_μ+p)σ(ν_μ+n-->μ^-+p)=0.11+/-0.015, R_ν¯≡σ(ν¯_μ+p-->ν¯_μ+p)σ(ν¯_μ+p-->μ⁺+n)=0.19+/-0.035, and R^NC≡σ(ν¯_μ+p-->ν¯_μ+p)σ(ν_μ+p-->ν_μ+p)=0.41+/-0.09 for 0.40<Q²<0.90 (GeV/c)² where -Q² is the square of the momentum transfer to the nucleon. The differential cross sections as functions of Q², d σ^νdQ² and d σ^ν¯dQ², are also determined. Our results are in good agreement with the Weinberg-Salam-Glashow-Iliopoulos-Maiani model of the weak and electromagnetic interactions and yield ²θ_W=0.28+/-0.03.