Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 172-177) / Microfiche. / xiii, 177 leaves, bound ill. 29 cm

Neutrino astronomy has the potential to greatly improve our understanding of the high-energy universe. An unresolved, diffuse, flux of neutrinos is sensitive to the properties of the population of cosmic accelerators in the universe. Data from 2008 and 2009 collected with the IceCube in-ice detector in a 40-string configuration were searched for an all-flavor ultra high-energy diffuse flux of astrophysical neutrinos. Data were divided into three streams based on signal and background event topology. Robustness was prioritized and a good agreement between real and simulated background data was observed. The search was optimized to give a high sensitivity to a neutrino flux with energy spectrum E-2 and energy greater than 1 PeV. The data sample used in the search for signal had a live time of 345.7 days and the estimated background was 1.2 ± 0.5 events. Taking systematic and statistical uncertainties into account, the sensitivity ΦS was estimated at E2 ΦS = 1.15 · 10-8 GeV cm-2 s-1 sr-1 assuming a 1:1:1 ratio between neutrino flavors at Earth. The full data sample was unblinded once the analysis procedure was fixed and approved by the IceCube collaboration. Three events survived the final filter level. The surviving events look like reasonable neutrino candidate events. Assuming a background only hypothesis, the probability of seeing three or more events is 10%. The resulting 90% confidence level upper limit ΦUL is the most strict to date with E2 ΦUL = 2.32 · 10-8 GeV cm-2 s-1 sr-1. The central 90% signal energy interval is 282 TeV to 214 PeV, and signal acceptance is distributed as 32% muon neutrinos, 39% electron neutrinos and 29% tau neutrinos. Several models for a diffuse extragalactic neutrino flux were excluded.

We construct a model which provides maximal mixing between a pseudo-Dirac Vµ/VT pair, based on a local U(1)Lµ-LT symmetry. Its strengths, weaknesses and phenomenological consequences are examined. A new intermediate range force is predicted, mediated by the light gauge boson of U(1)Lµ-LT. Through the mixing of µ, T and e, this force couples to electrons and thus may be searched for in precision “gravity” experiments.The generation of relic neutrino asymmetries in the early universe via the mechanism of partially coherent active-sterile neutrino oscillations is considered. We study how an approximate evolution equation for the growth of the asymmetry can be extracted from the exact Quantum Kinetic Equations which describe the evolution of the neutrino ensemble, and examine the nature of some of the approximations employed.

A study into the reconstruction of cascade like events in the IceCube neutrino detector was performed by utilizing in-situ flasher devices. Reconstruction analysis was done with two different flasher settings at each optical module on string 63 at varying depths in the ice. Three different reconstruction algorithms were used to estimate the characteristics of these cascade type events. The characteristics included the estimated vertex position, and the number of photons produced by each flasher. The number of photons produced can be related to the energy for the cascade event via the detailed knowledge of the cascade physics. Results from the analysis show the strengths of using the center of gravity type approaches to estimating the vertex positions of very bright events, and the inability to reconstruct to an accurate position in z which can occur when using more complicated vertex algorithms on the same events. Analysis using the energy reconstruction modules demonstrated the strengths of using methods that take into account the ice properties inside the detector.

Thesis (Ph.D.) - University of St Andrews, September 2008.

Thesis (M.S.)--State University of New York at Binghamton, Department or Physics, Applied Physics and Astronomy, 2008. / Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Karol Lang. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Chicago, Department of Physics, December 1999. / Includes bibliographical references. Also available on the Internet.

Thesis (M. Sc.)--Carleton University, 1995. / Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 1996. / Also available in electronic format on the Internet.