A Measurement of νe Appearance and νμ Disappearance Neutrino Oscillations with the NOvA Experiment

Author: Pershey, Daniel Stephen

Year: 2018

Degree: Dissertation (Ph.D.)

Advisor: Patterson, Ryan B.

Committee Members: Patterson, Ryan B.; Porter, Frank C.; Filippone, Bradley W.; Cheung, Clifford W.

Option: Physics

DOI: 10.7907/rc0w-zg32

Abstract

NOvA is a two-detector, neutrino oscillation experiment on an 810 km baseline in the NuMI beam at Fermilab. NuMI is an off-axis, narrow-band beam centered near 1.8 GeV and is configurable to send a high-purity νμ or -νμ neutrino flux which passes through the NOvA far detector, sensitive to νμ and -νμ disappearance and νe and -νe appearance. The NOvA near and far detectors are functionally identical, liquid scintillator trackers. They are finely segmented relative to the radiation length in the detectors allowing for the detailed reconstruction of electromagnetic shower necessary to identify νe CC events.

Through a joint analysis of the appearance and disappearance oscillation channels using neutrino and anti-neutrino data, NOvA constrains the allowed parameter space in δCP, the neutrino mass hierarchy, sin2θ23, and Δm232. We observe 58 and 18 appearance candidates on an expected background of 15.06 and 5.32 events in neutrino and anti-neutrino mode, respectively. This observation gives a 1.77σ preference for the normal mass hierarchy and 1.7σ preference for θ23 in the upper octant. NOvA will maintain its position as a long-baseline oscillation experiment with leading sensitivity for several more years in which time analysis will further disambiguate the fundamental neutrino parameters that determine oscillation behavior.

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