Normalized Small-yCross Sections for Neutrinos and Antineutrinos at High Energy

We present results on flux-normalized neutrino and antineutrino cross sections near $y=0\mathrm{}$ from data obtained in the Fermilab narrow-band beam. We conclude that values of ${\sigma }_0={\frac{d\sigma }{\mathrm{dy}}|}_{y=0\mathrm{}}$ are consistent with rising linearly with energy over the range $45<~E_{\nu }<~20.5$ GeV. The separate averages of $\nu$ and $\overline{\nu }$, each measured to 4%, are equal to well within the errors. The best fit for the combined data gives $\frac{{\sigma }_0}{E}=(0.719\mathrm{}\pm 0.035)\times {10}^{-38\mathrm{}}$ ${\mathrm{cm}}^2$/GeV at an average $E_{\nu }$ of 100 GeV.