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This thesis aims at the neutrino oscillations phenomena and the role of longbaseline neutrino oscillation experiments and NOνA in particular in oscillation parameters search. The standard formalism of 3 neutrinos model is described, NOνA experiment and its main features and physics goals (mixing angles θ13 and θ23, CP violation, the value of the CP phase δ and mass hierarchy determination) are introduced. The effects of media to neutrino propagation are explained and effective matter oscillation parameters are derived. The way to resolve the mass hierarchy exploiting matter effects in long-baseline neutrino oscillation experiments is depicted and consequent problems regarding the recent knowledge of oscillation parameters, i.e. δ-, θ13- and θ23-degeneracies, are discussed. In the last part GLoBES software is used to simulate NOνA results and to compute the estimated sensitivities to the mass hierarchy in case of 3 years ν run and 1.5ν+1.5ν years run in order to show the advantage of an earlier switch to antineutrino mode in mass hierarchy determination.

[pt] Nessa dissertação foi realizada uma revisão da teoria elementar das lentes gravitacionais, fazendo ênfase no estudo do efeito que tem a massa dos neutrinos no atraso gravitacional de sinais provenientes de fontes distantes e que são desviados quando passam perto de uma distribuição de massa localizada entre a fonte e o observador. Para isto, dentro dos limites de massa que fornecem os atuais experimentos de oscilação de neutrinos, decaimento beta e a cosmologia, se estudou a contribuição à densidade de energia não relativista que hoje têm os neutrinos de fundo cósmico. Em base a esses resultados, fizemos uma comparação porcentual entre a distância do diâmetro angular para um valor de massa do neutrino permitido e o valor da distância quando a massa é zero. Esta análise foi feita sob o arcabouço do modelo cosmológico padrão para dois casos possíveis da condição de normalização para os parâmetros de densidade de radiação e constante cosmológica são fixos e o segundo caso quando o parâmetro densidade de energia de matéria é fixo como também o parâmetro densidade de radiação e, portanto deixando variáveis os parâmetros densidade de neutrinos na medida do atraso das sinais é desprezível para o primeiro caso e tem uma contribuição de ordem de um por cento para o segundo caso. / [en] In the presente work I carried out an review of the elementar theory of gravitational lensing. It is mainly emphasizing to study the effect it would have neutrino mass in the time delay of signals from distant sources which are deflected due to the presence of a mass distribution that acts as a lens. To do this, for the mass values provided by neutrino oscillation, beta decay experiments and cosmology, we study the presente contribution of cosmic background neutrinos to energy density of universe. Based on these results, it was made a comparison between the angular diameter distance when the mass is zero. All this was done from the perspective of the standard cosmological model under two possible cases for the normalization condition of the energy density parameters presente in the universe: first, when the radiation and cosmological energy density parameters are fixed and second when the parameters for matter and radiation are fixed. It was found that the effect of the neutrino mass on time delay measurement is negligible for the first case and has a contribution of the order of one percent for the second case.

Ngai Wah Kai = 中微子混合角[theta]₁₃測量的最優化與本底研究 / 魏華佳. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 83-87). / Text in English; abstracts in English and Chinese. / Ngai Wah Kai = Zhong wei zi hun he jiao [theta]₁₃ ce liang de zui you hua yu ben di yan jiu / Wei Huajia. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Puzzle with Beta Decay Spectrum --- p.2 / Chapter 1.2 --- Detection of a Free Neutrino --- p.3 / Chapter 1.3 --- Properties of Neutrinos --- p.5 / Chapter 1.3.1 --- Neutrino Mass --- p.6 / Chapter 1.3.2 --- Dirac and Majorana Neutrinos --- p.7 / Chapter 1.3.3 --- Neutrino Oscillation --- p.8 / Chapter 1.4 --- Background to Underground Neutrino Experiments --- p.10 / Chapter 1.5 --- Outline of the Thesis --- p.12 / Chapter 2 --- The Last Mixing Angle and Daya Bay --- p.14 / Chapter 2.1 --- Current Status of Neutrino Oscillation --- p.14 / Chapter 2.2 --- Measurement of θ13 with Reactors --- p.19 / Chapter 2.3 --- "Daya Bay, the Site and the Detector" --- p.20 / Chapter 2.3.1 --- Overview --- p.20 / Chapter 2.3.2 --- Detector --- p.22 / Chapter 3 --- Detector Baseline Optimization --- p.24 / Chapter 3.1 --- Antineutrino Spectrum and Flux from Reactors --- p.25 / Chapter 3.1.1 --- Antineutrino Production --- p.25 / Chapter 3.1.2 --- Antineutrino Spectrum from Reactors --- p.26 / Chapter 3.2 --- Interaction Rate Analysis --- p.29 / Chapter 3.3 --- Spectral Analysis --- p.30 / Chapter 3.3.1 --- Effect of Three-Neutrino Mixing --- p.33 / Chapter 4 --- Energy Resolution of the Proposed Antineutrino Detector --- p.37 / Chapter 4.1 --- Physical Processes inside the Detector --- p.38 / Chapter 4.2 --- Simulation Algorithm --- p.39 / Chapter 4.3 --- Comparison of Different Detector Geometries and Configurations --- p.43 / Chapter 5 --- Aberdeen Tunnel Laboratory - A Satellite Lab of Daya Bay --- p.53 / Chapter 5.1 --- Geological Properties --- p.54 / Chapter 5.2 --- Research Plan and Methodology --- p.55 / Chapter 5.2.1 --- Detector Configuration --- p.55 / Chapter 5.2.2 --- Front-End Electronics --- p.58 / Chapter 5.2.3 --- Trigger System --- p.60 / Chapter 6 --- Cosmic Ray Muons and Induced Neutron Underground --- p.63 / Chapter 6.1 --- Background to Reactor Antineutrino Experiments --- p.63 / Chapter 6.1.1 --- Origins of the Fast Neutrons --- p.64 / Chapter 6.2 --- Muon Flux and Energy Spectrum Underground --- p.65 / Chapter 6.2.1 --- Muons at the Earth Surface --- p.66 / Chapter 6.2.2 --- Propagating Muons through Rock --- p.67 / Chapter 6.2.3 --- Flat Surface Case --- p.69 / Chapter 6.2.4 --- Aberdeen Mountain Case --- p.69 / Chapter 6.2.5 --- Pyramid Case --- p.72 / Chapter 6.2.6 --- Daya Bay Case --- p.73 / Chapter 6.3 --- Predicting Neutron Production from Cosmic Ray Muons --- p.76 / Chapter 6.3.1 --- Neutron Yield --- p.77 / Chapter 6.3.2 --- Neutron Energy Spectrum --- p.79 / Chapter 6.3.3 --- Neutron Angular Distribution --- p.80 / Chapter 6.3.4 --- Neutron Multiplicity --- p.81 / Bibliography --- p.83 / Chapter A --- Three-neutrino mixing formula --- p.88 / Chapter B --- Sea Level Muon Generator --- p.90 / Chapter B.1 --- Acceptance-rejection Method --- p.90 / Chapter B.2 --- Finding the Comparison Functions --- p.91 / Chapter B.3 --- Checking the Generator --- p.92 / Chapter C --- Circuit Diagrams of the Discrimination Board for Plastic Scintillators --- p.96

In this thesis, we investigate observable consequences of active and sterile neutrinos, in galactic, cluster, and cosmological scales. We assume that sterile neutrinos with masses of order 10's eV, 10's keV, and MeV were formed by oscillation of active neutrinos in the early universe. If sterile neutrinos with mass ∼ 30 eV exist, they affect the structure of galaxies and explain the flatness of their rotation curves. Also, the existence of decaying sterile neutrinos with mass 16 --- 18 keV and decay rate Gamma = (5 +/- 1) x 10--17 s--1 can simultaneously be the cause of heating at the Milky Way center, the supermassive blackhole mass and velocity dispersion relation, the lack of cooling flow in clusters, and reionization in the universe. Lastly, we make use of the observed 511 keV annihilation flux line at the Milky Way center to constrain properties of sterile neutrinos of MeV mass scale. We also derive a relation among several cluster observables assuming the existence of an active neutrino halo, which agrees with the observational data in 103 clusters. / Chan, Man Ho = 中微子天文物理 / 陳文豪. / Adviser: Ming-Chung Chu. / Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: . / Thesis submitted in: December, 2008. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 107-113). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307. / Chan, Man Ho = Zhong wei zi tian wen wu li / Chen Wenhao.

<p>Magnetic monopoles are hypothetical particles carrying isolated magnetic charges, analogous to electrically charged particles. They have never been observed in experiments, but there are theoretical indications that they might exist. Several experiments have been carried out over the years in order to detect monopoles, or to set upper limits on their abundance in the Universe.</p><p>In this work, underlying theory of the properties of magnetic monopoles is presented, together with some of the experiments performed in the past, the present and the future. Emphasis is put on AMANDA and other Cherenkov neutrino telescopes. Results of the described experimental searches are summarized.</p>

Graduation date: 2000

Magnetic monopoles are hypothetical particles carrying isolated magnetic charges, analogous to electrically charged particles. They have never been observed in experiments, but there are theoretical indications that they might exist. Several experiments have been carried out over the years in order to detect monopoles, or to set upper limits on their abundance in the Universe. In this work, underlying theory of the properties of magnetic monopoles is presented, together with some of the experiments performed in the past, the present and the future. Emphasis is put on AMANDA and other Cherenkov neutrino telescopes. Results of the described experimental searches are summarized.

Observations indicate that there is a correlation between long duration gamma-ray bursts (GRBs) and core-collapse supernovae (SNe). The leading model for GRB production assumes that relativistic jets are generated by the core-collapse within the progenitor star. Charged particles undergo Fermi-acceleration within internal shocks of these jets and subsequently give rise to gamma ray emission once the jets breach the surrounding stellar envelope. Very few SNe result in the occurrence of GRBs, however, it has been suggested that a significant fraction of core-collapse SNe manage to produce mildly relativistic jets. These jets are insufficiently energetic to break through the envelope and are effectively ’choked’ resulting in a lack of observed gamma ray emission. In both the failed and successful GRB scenario, neutrino production can occur if protons are accelerated in the internal shocks of these jets. These neutrinos may be detectable by the IceCube neutrino observatory and its low energy extension DeepCore. This thesis presents the methods and results of a dedicated search for temporal and spatial clustering of neutrino events during the IceCube 2012 data season. Examination of 22,040 neutrino event candidates acquired over a detector livetime of 330 days revealed no statistically significant transient source of neutrino emission. Limits on the rate of choked GRBs in the nearby universe for possible values of neutrino emission model parameters are presented.

Neutrinos (v) are interesting for many reasons; they are the only fundamental fermions which are electrically neutral; their mass is orders of magnitude smaller than the lightest charged lepton, the electron; and their solely weak interactions make them an excellent probe of the weak nuclear force. However, one of the most interesting aspects of neutrinos is that, unlike their charged lepton partners, neutrino mass and flavor eigenstates are not the same. All leptons possess 'lepton flavor', a property which is conserved in neutrino interactions. However, because of the difference in the mass and weak eigenstates of neutrinos, a quantum-interference effect is seen in the time evolution of neutrinos. This results in energy and distance dependent oscillations of the neutrino's lepton flavor called 'neutrino oscillations'. The MINOS experiment (Main Injector Neutrino Oscillation Search) was designed to measure the neutrino oscillation parameters, [Delta]m²₃₂ and sin²(2[theta]₃₂). MINOS is composed of two detectors located on a 'beam' of v[subscript mu]s. The MINOS Near Detector is located at Fermilab, and the Far Detector is located at the Soudan Mine in Minnesota, 734 km after the Near Detector. The MINERvA experiment (Main Injector Neutrino Experiment for v - A) is a neutrino experiment placed directly in front of the MINOS Near Detector. MINERvA's goal is to make precision measurements of neutrino cross sections. This will help with uncertainties in oscillation measurements, such as MINOS' at low energy. Although lepton flavor is conserved in neutrino interactions, the final state lepton can be a charged lepton ('charged current' interactions) or a neutrino ('neutral current' interactions) of a particular flavor. The identification of charged current ν[subscript mu] interactions through the identification of a muon in the final state is a critical component to both neutrino oscillation and cross section measurements; neutral current events are a background to the oscillation signal because the properties of the incoming neutrino cannot be determined. Such identification is particularly difficult and important for low-energy neutrino events. In this thesis, we will discuss improvements to the MINOS charged current identification at low energies, studies to estimate the effect of the neutral current background on the measurement of the oscillation parameters, and the aspects of muon identification which are similar for the MINOS and MINERvA experiments. In 2010, the MINOS experiment released a measurement of the oscillation parameters based on 7.32x10²⁰POT. The results were [Delta]m²₃₂ = 2.32⁺⁰̇¹²[subscript 0.08] x 10³eV², and sin²(2[theta]₃₂) > 0.90(90%,C.L.). This is the best measurement of the oscillation parameter, [Delta]m²₃₂, and a competitive measurement of sin²(2[theta]₃₂). The improvements to the charged current event selection helped MINOS observe a complete oscillation in neutrino energy. / text