Final-state kinematic imbalances are measured in mesonless production of νμ+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.
Bibliographical noteFunding Information:
This work was supported by the Fermi National Accelerator Laboratory under U.S. Department of Energy contract No. DE-AC02-07CH11359 which included the MINERvA construction project. Construction support was also granted by the United States National Science Foundation under Grant No. PHY-0619727 and by the University of Rochester. Support for participating scientists was provided by NSF and DOE (USA), by CAPES and CNPq (Brazil), by CoNaCyT (Mexico), by Proyecto Basal FB 0821, CONICYT PIA ACT1413, Fondecyt 3170845 and 11130133 (Chile), by Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica (CONCYTEC), Dirección de Gestión de la Investigación - Pontificia Universidad Católica del Peru (DGI-PUCP), and Vice-Rectorate for Research of National University of Engineering (VRI-UNI) (Peru), by the Latin American Center for Physics (CLAF), by Science and Technology Facilities Council (UK), and by NCN Opus Grant No. 2016/21/B/ST2/01092 (Poland). We thank the MINOS Collaboration for use of its near detector data. We acknowledge the dedicated work of the Fermilab staff responsible for the operation and maintenance of the beam line and detector and the Fermilab Computing Division for support of data processing.