Measurement of $$\Delta m^2_{32}$$ and $$\sin^2\!\theta_{23}$$ using Muon Neutrino and Antineutrino Beams in the NOvA Experiment
- Sussex U.
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 \numu~+~\numubar disappearance allows constraint of the $$|\Delta m^2_{32}|$$ and \sint oscillation parameters. This thesis presents the first 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 $$8.85\ti mes 10^{20}$$ and $$6.91\times 10^{20}$$~protons~on~target for neutrino and antineutrino data respectively. Under the assumption of a normal (inverted) neutrino mass hierarchy, analysis of the data gives $$\Delta m^2_{32}=+2.49^{+0.09}_{-0.07}\times10^{-3}~\text{eV}^2$$ ($$\Delta m^2_{32}=-2.54\pm0.08\times10^{-3}~\text{eV}^2$$) and $$\sin^2\theta_{23} = 0.59\pm0.03$$ ($$\sin^2\theta_{23} = 0.44\pm0.03$$). Maximal mixing ($$\sin^2\theta_{23} = 0.5$$) is disfavoured at the 1.7~\sig level.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1502822
- Report Number(s):
- FERMILAB-THESIS-2019-03; 1726090
- Country of Publication:
- United States
- Language:
- English
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