Charged pion production in νμ interactions on hydrocarbon at ⟨Eν⟩=4.0 GeV

Charged pion production via charged-current ν_μ interactions on plastic scintillator (CH) is studied using the MINERvA detector exposed to the NuMI wideband neutrino beam at Fermilab. Events with hadronic invariant mass W <1.4 GeV and W <1.8 GeV are selected in separate analyses: the lower W cut isolates single pion production, which is expected to occur primarily through the Δ (1232 ) resonance, while results from the higher cut include the effects of higher resonances. Cross sections as functions of pion angle and kinetic energy are compared to predictions from theoretical calculations and generator-based models for neutrinos ranging in energy from 1.5-10 GeV. The data are best described by calculations which include significant contributions from pion intranuclear rescattering. These measurements constrain the primary interaction rate and the role of final state interactions in pion production, both of which need to be well understood by neutrino oscillation experiments.