A cross section measurement from neutrino interactions on argon gas

• Main Author: Larkin, Edward
• Published: University of Warwick 2017
• Subjects: 539.7; QC Physics
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.714978

T2K is a neutrino oscillation experiment using an off-axis beam of muon neutrinos. We use its ND280 near detector to make measurements of neutrino interactions in argon gas. Long baseline neutrino experiments are approaching the point of being limited by systematic uncertainties on neutrino-nucleus cross sections rather than only statistics. This makes it imperative for a proper understanding of such processes to reduce their uncertainties. A gas interaction analysis provides a way to gain such an understanding. This thesis describes the first successful neutrino–nucleus cross section measurement performed on gas. The TREx reconstruction algorithms developed for this goal feature a novel path finding based pattern recognition algorithm and have now become the official TPC reconstruction software for the T2K experiment. The analysis itself uses real data and Monte Carlo based on the NEUT and GENIE neutrino interaction generators. The distributions of these results with respect to muon and proton kinematics and proton multiplicity are discussed in the context of differences between the two generators. The ND280 TPCs have the advantage of detailed reconstruction which affords unique opportunities to test the agreement with data of nuclear models used in simulation. Future generations of this analysis are expected to produce more varied and precise measurements in this vein.