Measurement of Atmospheric Muon Neutrino Disappearance with IceCube-DeepCore

Open Access
Author:
Dunkman, Matthew Gregory
Physics
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
May 27, 2015
Committee Members:
• Tyce De Young, Dissertation Advisor
The measurement of muon neutrino disappearance presented here was designed to make use of neutrinos of all flavors, exploiting $\nu_e$ events and more poorly reconstructed cascade-like neutrino events to better constrain systematic uncertainties associated with neutrino fluxes and interactions. In accordance with IceCube Collaboration policy, the analysis was developed blind,'' with reference to Monte Carlo simulations and down-going events where no oscillation signal could be visible. Discrepancies observed in the data when they were examined after the analysis was finalized led to the conclusion that the cascade-like and intermediate data samples were affected by unexpected systematic effects, so that their inclusion in the analysis produced substantial bias. This analysis thus relied exclusively on the track-like data sample, while investigations into the nature of these systematic effects continue in preparation for an IceCube journal article. The best fit and 68\% confidence interval from this analysis on the two oscillation parameters which drive muon neutrino disappearance are \begin{align*} \sin^2 \theta_{23} &= 0.53_{-0.11}^{+0.07}, \\ \Delta m_{32}^2 / 10^{-3}\mathrm{eV}^2 &= 2.35_{-0.17}^{+0.14}, \end{align*} which are compatible and competitive with measurements made by dedicated beam-line neutrino experiments.