Constraints on neutrino oscillation parameters with the NOvA experiment
- Iowa State U.
NOvA is a long-baseline neutrino oscillation experiment, which consists of two finely-segmented liquid-scintillator detectors operating 14 mrad off-axis from the NuMI muon neutrino beam. With an 810 km baseline, the combined measurements of muon neutrino disappearance and electron neutrino appearance allow the determination of neutrino oscillation unknowns, namely the mass hierarchy, the octant of the largest neutrino mixing angle, and the CP violating phase. In this dissertation I present the joint analysis of $$\nu_\mu \to \nu_\mu$$ and $$\nu_\mu \to \nu_e$$ oscillation data with an exposure of $$8.85\times10^{20}$$ protons on target on the 14 kton detector. It includes the estimation of neutrino energy distributions in the far detector using near detector data constraints, details of the implementation of the simultaneous fit of \numu and \nue samples, and the effect of systematic uncertainties on the measurement of oscillation parameters. I also discuss NOvA's projected sensiti vity to determine the mass hierarchy and discover CP violation in future analyses with increased exposure and the addition of antineutrino datasets. With 66 electron neutrino and 126 muon neutrino candidates, the best fit to the data corresponds to the normal mass hierarchy, $$\Delta m^2_{32}=2.44\times 10^{-3} eV^2/c^4$$, $$\sin^2 \theta_{23}=0.56$$, and $$\delta_{CP} = 1.21\pi$$, with the allowed regions $$\Delta m^2_{32} \in [2.37,2.52]\times 10^{-3} eV^2/c^4$$, $$\sin^2 \theta_{23} \in [0.43,0.51] \cup [0.52,0.60]$$ and $$\delta_{CP} \in [0,0.12\pi] \cup [0.91\pi,2\pi]$$ at the 68.3\% C.L. Our data disfavor maximal mixing by 0.8$$\sigma$$, $$\delta_{CP} = \pi/2$$ in the inverted hierarchy at higher than 3$$\sigma$$, and the entire inverted mass hierarchy at the 95\% confidence level. % By increasing the size of the samples and adding anti-neutrino data, \nova can potentially resolve the neutrino mass hierarchy at 4$$\sigma$$ C.L. or higher for some combinations of oscillation parameters. Im provements to the sensitivity to the determination of the ma! ss hierarchy and CP violation in the neutrino sector can be achieved through gains in the NuMI beam intensity, the inclusion of external data, and refinements in the analysis methodology.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1498546
- Report Number(s):
- FERMILAB-THESIS-2018-29; 1724268
- Country of Publication:
- United States
- Language:
- English
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Constraints on neutrino oscillation parameters with the NOvA experiment
Thesis/Dissertation
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Sun Dec 31 23:00:00 EST 2017
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OSTI ID:1712775