Measurement of the Low E_available Multi-Neutron Antineutrino Cross Section at <E_ν> ~ 6 GeV

Measuring (anti)neutrino energy is critical for oscillation experiments.  Neutrons introduce uncertainty and bias into (anti)neutrino energy estimators because they are difficult to reconstruct.  Different rates of neutron production by neutrinos and antineutrinos and the role of neutrons in interactions on correlated nucleon pairs amplify the impact of neutron production models on oscillation experiments.  The relative paucity of antineutrino neutron production measurements makes them even more valueable.  We present a preliminary antineutrino multi-neutron cross section measurement at low E_available on the MINERvA detector's hydrocarbon scintillator at <E_ν> ~ 6 GeV.  Interactions on correlated nucleon pairs are predicted to comprise a large fraction of this channel.  We compare our result to alternative antineutrino interaction models to illuminate opportunities for advances in the theory of neutron production by antineutrinos.