Electron neutrino appearance in the MINOS experiment

Citation

Orchanian, Mhair-Armen Hagop (2012) Electron neutrino appearance in the MINOS experiment. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:05302012-124605015

Abstract

This thesis describes a search for $\nu_e$ appearance in the two-detector long-baseline MINOS neutrino experiment at Fermilab, based on a data set representing an exposure of $8.2 \times 10^{20}$ protons on the NuMI target. The analysis detailed herein represents an increase in sensitivity to the $\theta_{13}$ 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 $\theta_{13}$ further, finding $2\sin^2 \theta_{23} \sin^2 2\theta_{13} < 0.12 (0.20)$ at the 90\% confidence level for $\delta_\mathrm{CP} = 0$ and the normal (inverted) neutrino mass hierarchy. The best-fit value is $2\sin^2 \theta_{23} \sin^2 2\theta_{13} = 0.041^{+0.047}_{-0.031} (0.079^{+0.071}_{-0.053})$ under the same assumptions. We exclude the $\theta_{13}=0$ hypothesis at the 89\% confidence level.

Thesis Files