Many experiments have provided evidence for neutrino flavor oscillations, and consequently that neutrinos are in fact massive which is not predicted by the Standard Model. Many experiments have been built to constrain the parameters which determine flavor oscillations, and for only three flavors of neutrinos the mixing parameters are well known, aside from the CP violating phase for two mass hierarchies. Most experimental data can be well explained by mixing between three flavors of neutrinos, however oscillation anomalies from several experiments, most notably from LSND (Liquid Scintillator Neutrino Detector) have suggested that there may be additional flavors of neutrinos beyond those in the Standard Model. One of the focuses of this dissertation is the possibility of adding new flavors of right-handed neutrinos to the Standard Model to account for oscillation anomalies, and exploring the consequences of sterile neutrinos for other experiments.Sensitivities to a particular model of sterile neutrinos at the future Long-Baseline Neutrino Experiment will be determined, in which CP effects introduced by the sterile neutrinos play an important role. It will be demonstrated how, by combining data from the Long-Baseline Neutrino Experiment along with data from Daya Bay and T2K, it is possible to provide evidence for or rule out this model of sterile neutrinos.A chi-squared analysis is used to determine the significance of measuring the effects of sterile neutrinos in IceCube; it will be shown that it may be possible to extract evidence for sterile neutrinos from high energy atmospheric neutrinos in IceCube. Furthermore it will be demonstrated how measuring neutrino flavor ratios from astrophysical sources in IceCube can help to distinguish between the three flavor scenario and a beyond the Standard Model (BSM) scenario involving sterile neutrinos. Measuring astrophysical as well as atmospheric neutrinos can evince the existence of sterile neutrinos.Despite the fact that the mixing parameters for the three Standard Model neutrino flavors are well known, some implications of neutrino interactions for flavor oscillations are not well understood. Neutrinos can interact with one another in a similar way to how neutrinos interact with normal matter. Neutrino-neutrino forward scattering can lead to a flavor swap for the propagating neutrino, or the propagating neutrino can retain its original flavor. These interactions contribute an effective potential to the Hamiltonian describing the flavor evolution which depends on a background neutrino density. In normal matter the neutrino density is very low which allows for neutrino-neutrino interactions to be ignored, however these interactions can dominate over vacuum and normal matter interactions in very dense environments such as core-collapse supernovae and early universe scenarios.Neutrino-neutrino interactions give rise to terms quadratic in neutrino densities in the equations of motion, and can give rise to what is called collective oscillations resulting from interference with vacuum and normal matter effects. The non-linearity has made the problem of solving for collective oscillations analytically intractable without simplifying assumptions, and has made this a problem relegated to supercomputer simulations. This dissertation is concerned with analytic methods for solving the equations of motion for core-collapse neutrino propagation. It will be shown here that, by keeping only $\nu\nu$-interactions at initial distances outward from the supernova core, it is possible to solve the equations of motion by factorizing vacuum oscillations and the effects of $\nu\nu$-interactions. Furthermore, it will be shown how using this factorization scheme it is possible to predict where flavor oscillations become unstable. This is an important development because it can allow one to predict the neutrino flux in Earth experiments from core-collapse supernovae, while at the same time gaining an understanding of the underlying physics involved in complicated processes such as collective oscillations and the rapid growth of oscillations at medium range distances. Using the factorization ansatz together with a measured supernova spectrum it is possible in principle to determine the thermal spectra inside of the supernova.

Neutrinos are fundamental particles which only interact via gravity and the weak force, which makes them uniquely hard to observe and study experimentally. There are three flavors in the Standard Model (SM) of particle physics, however there has been experimental results that suggest the existence of a theoretical fourth neutrino flavor, called the sterile neutrino, with the three flavors in the SM being active neutrinos. Sterile neutrinos would interact only via the gravity, which means we would only be able to detect them through neutrino oscillations. A potential environment in which active to sterile oscillations could be highly probable to occur is supernovae, due to a large amount of neutrinos being created through nuclear fusion as well as high and varying densities of matter through which the neutrinos propagate. To investigate the evolution of neutrinos in supernova environments and the possibility of stimulated sterile neutrino oscillations, we create a code to simulate the evolution of neutrinos through a supernova density profile.

Reviews the current state of knowledge of neutrino masses and the related question of neutrino oscillations. After an overview of the theory of neutrino masses and mixings, detailed accounts are given of the laboratory limits on neutrino masses, astrophysical and cosmological constraints on those masses, experimental results on neutrino oscillations, the theoretical interpretation of those results, and theoretical models of neutrino masses and mixings. The book concludes with an examination of the potential of long-baseline experiments. This is an essential reference text for workers in elementary-particle physics, nuclear physics, and astrophysics.

Since the discovery of neutrino oscillations neutrino physics has become an interesting field of research in physics. They imply that neutrino must have a small mass and that the neutrinos, coupled to the charged leptons, are mixtures of the mass eigenstates, analogous to the flavor mixing of the quarks. The mixing angles for the quarks are small, but for the leptons two of the mixing angles are large. The masses of the three neutrinos must be very small, less than 1 eV, but from the oscillation experiments we only know the mass differences -- the absolute masses are still unknown. Also we do not know, if the masses of the neutrinos are Dirac masses, as the masses of the charged leptons and of the quarks, or whether they are Majorana masses.In this volume, an overview of the present state of research in neutrino physics is given by well-known experimentalists and theorists. The contents -- originated from talks and discussions at a recent conference addressing some of the most pressing open questions in neutrino physics -- range from the oscillation experiments to CP-violation for leptons, to texture zero mass matrices and to the role of neutrinos in astrophysics and cosmology.

Neutrino oscillation (N.O.) is the only firm evidence of the physics beyond the Standard Model of particle physics and is one of the hottest topics in elementary particle physics today. This book focuses on the N.O., from its history to the future prospects, from the basic theories to the experiments. Various phenomena of N.O. are described intuitively with thorough explanations of the fundamental physics behind well-known formulations. For example, while many textbooks start with a discussion of the mixing matrix, this book stresses that N.O. is caused by the transition amplitudes between different neutrino flavors, and that the purpose of N.O. experiments is to measure transition amplitudes and think of its origin. The current understanding of neutrino oscillation is also summarized using the most up-to-date measurements, including the recently measured neutrino mixing angle θ13, and the future prospects of N.O. studies are described as well. The level of this book makes it a bridge between introductory textbooks and scientific papers.

Contents:Solar Neutrinos:The Latest Solar Neutrino Results in Super-Kamiokande (Y Koshio)Weak Current in Deuterium (T Sato)Solar Neutrino Phenomenology and Future:Solar Neutrino Oscillations (M C Gonzalez-Garcia)The Status of Resonant Spin Flavor Precession (C S Lim)Atmospheric Neutrinos:Status of the Atmospheric Neutrino Studies (M D Messier)Cosmic Ray Measurements for Atmospheric Neutrino with BESS-TeV (K Abe)Oscillation Phenomenology I:Calculations of the Atmospheric ν Fluxes (P Lipari)Three-Flavor Analysis of Atmospheric and Solar Neutrinos (A Marrone)Absolute Neutrino Mass:Neutrinoless Double Beta Decay and Neutrino Oscillations (H V Klapdor-Kleingrothaus)Accelerator Neutrinos, CPV:The MINOS Experiment (M D Messier)The JHF-Kamioka Neutrino Project (T Kajita)Models and GUTs:Proton Decay in the Semi-Simple Unification Model (T Watari)Leptogenesis via LHu Flat Direction (M Fujii)Lepton Flavor Violation:Probing Physics Beyond the Standard Model from Lepton Sector (J Hisano)Oscillation Phenomenology II:Four Puzzles of Neutrino Mixing (S M Barr)Supernova Neutrinos:Supernova Neutrinos (J F Beacom)and other papers Readership: Researchers in high energy physics. Keywords:Solar Neutrinos;Atmospheric Neutrinos;Oscillation Phenomenology;Neutrino Mass;Accelerator Neutrinos;CP Violation;GUTs;Lepton Flavor Violation;Supernova Neutrinos

This volume brings together international experts in diverse areas of physics to discuss recent progress in the experimental and theoretical study of neutrino oscillations.Readers are brought up to date with the latest developments in important neutrino experiments, and the associated progress in theory is summarized. The principal projects worldwide, such as Super-Kamiokande, SNO, KamLAND, are considered, and contributions also report on future experiments, including JPARC, OPERA, and MINOS.Several other related topics, such as dark matter, double beta decay, lepton flavor violation, and cosmology, are discussed, reflecting the wide-ranging specializations of many contributors outside of pure neutrino physics.