Measurement of ν¯μ charged-current single π− production on hydrocarbon in the few-GeV region using MINERvA

The semiexclusive channel ${\ensuremath{\nu}}_{\ensuremath{\mu}}+\mathrm{CH}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}+\text{nucleon}(\mathrm{s})$ is analyzed using MINERvA exposed to the low-energy NuMI ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ beam with spectral peak at ${E}_{\ensuremath{\nu}}\ensuremath{\simeq}3\text{ }\text{ }\mathrm{GeV}$. Differential cross sections for muon momentum and production angle, ${\ensuremath{\pi}}^{0}$ kinetic energy and production angle, and for squared four-momentum transfer are reported, and the cross section $\ensuremath{\sigma}({E}_{\ensuremath{\nu}})$ is obtained over the range $1.5\text{ }\text{ }\mathrm{GeV}\ensuremath{\le}{E}_{\ensuremath{\nu}}l20\text{ }\text{ }\mathrm{GeV}$. Results are compared to GENIE and NuWro predictions and to published MINERvA cross sections for charged-current ${\ensuremath{\pi}}^{+}({\ensuremath{\pi}}^{0})$ production by ${\ensuremath{\nu}}_{\ensuremath{\mu}}({\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}})$ neutrinos. Disagreements between data and simulation are observed at very low and relatively high values for muon angle and for ${Q}^{2}$ that may reflect shortfalls in modeling of interactions on carbon. For ${\ensuremath{\pi}}^{0}$ kinematic distributions, however, the data are consistent with the simulation and provide support for generator treatments of pion intranuclear scattering. Using signal-event subsamples that have reconstructed protons as well as ${\ensuremath{\pi}}^{0}$ mesons, the $p{\ensuremath{\pi}}^{0}$ invariant mass distribution is obtained, and the decay polar and azimuthal angle distributions in the rest frame of the $p{\ensuremath{\pi}}^{0}$ system are measured in the region of $\mathrm{\ensuremath{\Delta}}(1232{)}^{+}$ production, $Wl1.4\text{ }\text{ }\mathrm{GeV}$.