Neutrino-hydrogen interactions in the SAND detector of the DUNE experiment

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long base-line neutrino program, exposed to the world’s most intense neutrino beam. DUNE is designed to measure the CP violation phase, to determine the neutrino mass ordering, and to improve the precision of oscillation parameters. Its near detector complex plays a central role in constraining the neutrino flux and interaction models that dominate the systematic uncertainties of the oscillation analysis. A major limitation arises from large uncertainties in the neutrino-nucleus cross section, driven by nuclear modeling and final-state interactions. A promising strategy to overcome this challenge is to measure neutrino interactions on hydrogen, where the cross sections are known with much smaller uncertainties. This work focuses on the SAND detector (System for on-Axis Neutrino Detection) located at the DUNE near site and details a methodology for achieving recise measurements of (anti)neutrino interactions on hydrogen in its low-density tracker. The approach relies on the statistical subtraction of interactions observed on thin graphite targets from those on polypropylene ("solid hydrogen" technique). This capability is investigated through a full detector simulation. An estimate of the systematic uncertainties on the energy distribution of (anti)neutrino on hydrogen is provided.