Study of Neutrino interactions on Hydrogen in the SAND detector of DUNE

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation project. Its primary goals are to measure the possible violation phase (delta CP) and determine the sign of the mass squared difference ($\Delta m^{2}_{13}$), which is crucial for understanding the neutrino mass hierarchy. DUNE will exploit a Far Detector consisting of four multi-kiloton Liquid Argon Time Projection Chambers (LArTPCs) and a Near Detector (ND) complex situated near the neutrino source at Fermilab. One of the main limitations on the achievable precision on the measure of the neutrino flux, are the large uncertainties on neutrino cross-section on nuclei, which stems from the choice of a nuclear model and of final state interactions, that cannot be calculated in perturbative QCD. The measurement of neutrino interactions on free nucleon would instead allows to minimize the uncertainties on the flux, because the neutrino cross-section on free nucleon is known with much lower uncertainty. The SAND detector uses a low-density tracker in a magnetic field combined with a high-granularity calorimeter with high neutron detection efficiency and exceptional timing resolution to distinguish interactions on Hydrogen from those on nuclei. This thesis explores a detailed approach to achieve precise (anti)neutrino on Hydrogen measurements by statistically subtracting interactions on thin graphite targets (pure C) from those on polypropylene (C3H6) targets (solid Hydrogen concept). With the neutrino-Hydrogen cross-section known to percent-level precision, this study demonstrates that SAND can measure the flux with uncertainties at the few-percent level, with margins for future improvements.