Measurement of Atmospheric Muon Neutrino Disappearance with IceCube-DeepCore

Open Access
Dunkman, Matthew Gregory
Graduate Program:
Doctor of Philosophy
Document Type:
Date of Defense:
May 27, 2015
Committee Members:
  • Tyce De Young, Dissertation Advisor/Co-Advisor
  • Douglas Cowen, Dissertation Advisor/Co-Advisor
  • Irina Mocioiu, Committee Member
  • Stephane Coutu, Committee Member
  • Derek Brindley Fox, Committee Member
  • IceCube
  • DeepCore
  • Atmospheric neutrino
  • Neutrino oscillation
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.