Observation of Elastic Neutrino-Proton Scattering

Abstract

We have observed thirty events of the process $\nu p\to \nu p$ with a background expectation of seven events. The neutral-current to charged-current ratio $\frac{\sigma (\nu p\to \nu p)}{\sigma (\nu n\to {\mu }^{-}p)}$ is measured to be 0.17±0.05 for $0.3<\mathrm{}{q}^2<0.9\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ where $-q^2$ is the square of the four-momentum transfer to the proton.