Demonstration of neutron identification in neutrino interactions in the MicroBooNE liquid argon time projection chamber

A significant challenge in measurements of neutrino oscillations is reconstructing the incoming neutrino energies. While modern fully-active tracking calorimeters such as liquid argon time projection chambers in principle allow the measurement of all final state particles above some detection threshold, undetected neutrons remain a considerable source of missing energy with little to no data constraining their production rates and kinematics. We present the first demonstration of tagging neutrino-induced neutrons in liquid argon time projection chambers using secondary protons emitted from neutron-argon interactions in the MicroBooNE detector. We describe the method developed to identify neutrino-induced neutrons and demonstrate its performance using neutrons produced in muon-neutrino charged current interactions. The method is validated using a small subset of MicroBooNE’s total dataset. The selection yields a sample with 60% of selected tracks corresponding to neutron-induced secondary protons. At this purity, the integrated efficiency is 8.4% for neutrons that produce a detectable proton.. Authors: Abratenko, P. [Tufts Univ., Medford, MA (United States); MicroBooNE Collaboration. et al.]; Alterkait, O.; Aldana, D. Andrade; Arellano, L.; Asaadi, J.. DOE Contract: 89243024CSC000002; AC02-06CH11357; AC02-07CH11359; SC0007859; SC0012704. Subjects: 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS