Measurement of Ratios of νμ Charged-Current Cross Sections on C, Fe, and Pb to CH at Neutrino Energies 2–20 GeV

We present measurements of $\nu_{\mu}$ charged-currentcross section ratios on carbon, iron, and lead relative to a scintillator (CH) using the fine-grained MINERvA detector exposed to the NuMIneutrino beam at Fermilab. The measurements utilize events of energies $2 =8~GeV$, which have a reconstructed $\mu^{-}$ scattering angle less than $17^\circ$ to extract ratiosof inclusive total cross sections as a function of neutrino energy $E_{\nu}$ and flux-integrated differential cross sections with respect to the Bjorken scaling variable $x$. These results provide the first high-statistics direct measurements of nuclear effects in neutrino scattering using different targets in the same neutrino beam. Measured cross section ratios exhibit a relative depletion at low $x$ and enhancement at large $x$. Both become more pronounced as the nucleon number of the target nucleus increases. The data are not reproduced by GENIE, a conventional neutrino-nucleus scattering simulation, or by the alternative models for the nuclear dependence of inelastic scattering that are considered.