Electron Neutrino Appearance in the MINOS Experiment

Author: Orchanian, Mhair-Armen Hagop

Year: 2012

Degree: Dissertation (Ph.D.)

Advisor: Newman, Harvey B.

Committee Members: Newman, Harvey B.; Porter, Frank C.; Weinstein, Alan Jay; Wise, Mark B.

Option: Physics

DOI: 10.7907/T4JJ-BM32

Abstract

This thesis describes a search for νe appearance in the two-detector long-baseline MINOS neutrino experiment at Fermilab, based on a data set representing an exposure of 8.2 x 1020 protons on the NuMI target. The analysis detailed herein represents an increase in sensitivity to the θ13 mixing angle of approximately 25% over previous analyses, due to improvements in the event discriminant and fitting technique. Based on our observation, we constrain the value of θ13 further, finding 2sin2θ23 sin22θ13 < 0.12 (0.20) at the 90% confidence level for δCP = 0 and the normal (inverted) neutrino mass hierarchy. The best-fit value is 2sin2θ23 sin22θ13 = 0.041+0.047-0.031(0.079+0.071-0.053) under the same assumptions. We exclude the θ13 = 0 hypothesis at the 89% confidence level.

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