MEASUREMENT OF ATMOSPHERIC TAU NEUTRINO APPEARANCE WITH ICECUBE/DEEPCORE
Open Access
- Author:
- Huang, Feifei
- Graduate Program:
- Physics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 09, 2018
- Committee Members:
- Douglas Cowen, Dissertation Advisor/Co-Advisor
Douglas Cowen, Committee Chair/Co-Chair
Miguel Alejandro Mostafa, Committee Member
Stephane Coutu, Committee Member
Derek Brindley Fox, Outside Member - Keywords:
- tau neutrino appearance
neutrino oscillations
IceCube
DeepCore
atmospheric neutrinos
experimental results - Abstract:
- IceCube is a neutrino detector located inside a cubic kilometer of ice at the South Pole. Its geometry design makes it able to measure neutrinos in a large energy range from as low as 5~GeV up to a few PeV. The low energy subarray DeepCore can measure neutrinos as low as 5 GeV to roughly 100~GeV. This dissertation presented a measurement of atmospheric tau neutrino appearance with three years of IceCube/DeepCore data. The key physics parameter is $\nu_\tau~\rm{(CC+NC)\ normalization}$, a scale factor assigned to the signal $\nu_\tau$ (CC+NC) events, varying between 0 and 1, where the value of one corresponds to the expected rate assuming the standard three-flavor neutrino oscillations. The best fit $\nu_\tau~\rm{(CC+NC)\ normalization}$ was 0.59 with the $68\%$ C.I. in [0.34, 0.90], $\it{i.e.}$, $0.59_{-0.25}^{+0.31}$. The 90\% C.I. was [0.18, 1.12]. This corresponds to 1379 $\nu_\tau$ events out of a total of 40,959 events (which includes 39,070 all-neutrino-flavor events and 1,889 atmospheric muons). To compare with two previous experiments, the measurement of $\rm{\nu_{\tau}~CC}$ normalization was also conducted, where a scale factor $\nu_\tau \ \rm{CC\ normalization}$ is assigned to the signal $\nu_\tau$ CC-only events. The best fit $\nu_\tau \ \rm{CC\ normalization}$ was 0.43, with the 68\% C.I. being [0.12, 0.80], $\it{i.e.}$, $0.43_{-0.43}^{+0.36}$, and the $90\%$ C.I. was [0, 1.07]. Both the measured $\nu_\tau~\rm{(CC+NC)\ normalization}$ and $\nu_\tau \ \rm{CC\ normalization}$ are consistent with existing measurements and the standard three-flavor oscillation paradigm at 90\% C.L.