Measurement of $\Delta m^2_{32}$ and $\sin^2\!\theta_{23}$ using Muon Neutrino and Antineutrino Beams in the NOvA Experiment [report]

Tristan Blackburn
2019 unpublished
NOvA is a long-baseline neutrino oscillation experiment located in the mid-west United States. It consists of two functionally identical tracking calorimeters, known as the near and far detector, that measure neutrino interactions induced by the NuMI beam at baselines of 1 km and 810 km. NuMI can be configured to provide a muon neutrino or antineutrino beam. Analysis of ν µ + ν µ disappearance allows constraint of the |∆m 2 32 | and sin 2 θ 23 oscillation parameters. This thesis presents the
more » ... st NOvA disappearance results using both neutrino and antineutrino data -previous NOvA analyses have only used neutrino beam data. Two analysis improvements are delineated in dedicated chapters -the design of selection criteria to identify events that are fully contained in the far detector and the optimization of particle identification selection criteria in a multi-dimensional parameter space. The full-detector equivalent beam exposures used for this thesis are 8.85 × 10 20 and 6.91 × 10 20 protons on target for neutrino and antineutrino data respectively. Under the assumption of a normal (inverted) neutrino mass hierarchy, analysis of the data gives ∆m 2 32 = +2.49 +0.09 −0.07 ×10 −3 eV 2 (∆m 2 32 = −2.54±0.08×10 −3 eV 2 ) and sin 2 θ 23 = 0.59±0.03 (sin 2 θ 23 = 0.44 ± 0.03). Maximal mixing (sin 2 θ 23 = 0.5) is disfavoured at the 1.7 σ level. iv
doi:10.2172/1502822 fatcat:uvkgmjuit5gx5i3rhjt5hetyz4