Neutral currents predicted by weak-interaction models of the type discussed by Weinberg may be detected in neutrino reactions. Limits on the ratio $R$ of $\sigma (\nu +N\to \nu +X)$ to $\sigma (\nu +N\to {\mu }^{-}+X)$ are obtained independent of any dynamical assumption. For the total cross section for high-energy neutrinos, we find $R\ge 0.18$, provided the Weinberg mixing angle satisfies ${{sin}^2\theta }_W\le 0.33$. For the production of a single ${\pi }^0$ we find $R^{\prime }\ge 0.50$ contrasted with the experimental result $R^{\prime }\le 0.14$ using only the assumption of (3,3)-resonance dominance. Applications are also given to antineutrino reactions.

• Received 9 August 1972

DOI:https://doi.org/10.1103/PhysRevD.7.91