Search for 2p2h Interactions in the NOνA Near Detector

The physics of 2p2h interactions and their contribution to the NO$\nu$A near detector data are not fully understood. This study attempts to shed some light on these interactions and the accuracy of the models used to simulate them through a search for a specific 2p2h interaction in the NO$\nu$A near detector. By performing an event selection algorithm based on particle identifier algorithms run over reconstructed data, a signal region is created to minimize the background while maximizing the number of 2p2h events where a muon neutrino interacts with a neutron and a proton coupled by a meson exchange current and produces two protons and one muon. In the signal region, separation is found between the signal events and the background in plots of the angles between the protons and the muon. Although a full statistical analysis is not completed in this study, comparing the angle plots for simulation and data shows that the model used to simulate the events reasonably approximates reality and that the near detector data likely includes signal events. Signal events are also identified in event displays, further indicating that there is some contribution of the signal to the overall NO$\nu$A near detector data.