Measurement of Final-State Correlations in Neutrino Muon-Proton Mesonless Production on Hydrocarbon at ⟨Eν⟩=3  GeV

Abstract

Final-state kinematic imbalances are measured in mesonless production of ν_{μ}+A→μ^{-}+p+X in the MINERvA tracker. Initial- and final-state nuclear effects are probed using the direction of the μ^{-}-p transverse momentum imbalance and the initial-state momentum of the struck neutron. Differential cross sections are compared to predictions based on current approaches to medium modeling. These models underpredict the cross section at intermediate intranuclear momentum transfers that generally exceed the Fermi momenta. As neutrino interaction models need to correctly incorporate the effect of the nucleus in order to predict neutrino energy resolution in oscillation experiments, this result points to a region of phase space where additional cross section strength is needed in current models, and demonstrates a new technique that would be suitable for use in fine-grained liquid argon detectors where the effect of the nucleus may be even larger.

Pion-proton correlation in neutrino interactions on nuclei

“…The recent development of data analysis techniques [4,5] allows the for separation of QE from non-QE processes in the aforementioned zero-pion (0π) topology. And yet, the remaining RES-referred to as absorbed-pion events in this work-and 2p2h contributions occupy very similar phase space not only in the single-particle kinematics but also in the kinematic imbalance exploited by those techniques [6,7]. Their experimental evidence is the otherwise unaccounted for measured excess of event rates [8,9].…”

“…To characterize the impact of nuclear effects on the asymmetry, we organize the simulated events according to the transverse momentum imbalance [4,6,7],…”

Implementation of the SuSAv2-meson exchange current 1p1h and 2p2h models in GENIE and analysis of nuclear effects in T2K measurements

“…However, despite their notable size, such differences would be difficult to observe in any CC0π or inclusive measurement because of the large uncertainty on the 1p1h component which dominates the cross-section. More exclusive measurements, including information of the proton(s) in the final state have been performed in T2K [53] and Minerva [54] in order to enhance the sensitivity to 2p2h and will be discussed in Sec. V.…”

Measurements of neutrino-nucleus scattering

“…Both T2K [15,16] and MINERvA [17,18,19] have made measurements as a function of outgoing muon kinematics which show broad agreement with the available CC0π models, but are not very sensitive to nuclear effects, and lack power to differentiate between competing models, although certain tricks can be used to improve the sensitivity [20]. Additional variables, based on momentum imbalances have been proposed [21], and measured, again by both T2K [22] and MINERvA [23]. These measurements also require the reconstruction of a proton in the final state, and appear to be a powerful new tool for differentiating between models [24].…”