The NOνA experiment is a long-baseline neutrino oscillation experiment designed to measure electron neutrinos (νe) appearing in the NuMI beam, a muon neutrino (νµ) source at Fermilab. Its two detectors, Near and Far, are functionally identical active tracking calorimeters. This thesis is focused on the relative calibration of the Near Detector. The individual steps of the process, threshold, shadowing and attenuation calibration, are described. For the calibration, NOνA standardly uses cosmic muons. Alternative source, so called rock muons which are muons that originated from interactions of beam νµs with a rock surrounding the Near Detector, is introduced. The thesis guides through the development of selection criteria used to distinguish rock muon tracks from the data. Selected sample of rock muon tracks is used for the relative calibration and at each step the results are compared to the cosmic muons based calibration. The whole analysis is performed using simulated Monte Carlo data. 1

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22242号 / 理博第4556号 / 新制||理||1654(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 中家 剛, 准教授 WENDELL Roger, 教授 鶴 剛 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Das IceCube Neutrino Observatorium am Südpol hat die Existenz eines diffusen astrophysikalischen Neutrinoflusses nachgewiesen. Die Flavor-Zusammensetzung astrophysikalischer Neutrinos trägt Informationen über Orte kosmischer Teilchenbeschleunigung und Auswirkungen potenzieller neuer Physik auf die Neutrinoausbreitung. Zur seiner Bestimmung ist die Beobachtung von Tau-Neutrinos nötig. Ab einer Energie von ~O(100 TeV) kann deren Wechselwirkung über geladene Ströme eine Doppelkaskaden-Topologie ergeben, bei der die zwei Energiedepositionen am Tau-Entstehungs- und Tau-Zerfallsvertex aufgelöst werden können. Diese wird zusammen mit den bereits bekannten Topologien Einzel-Kaskade und Spur zur Messung der Flavor-Zusammensetzung auf der Erde benutzt. In dieser Arbeit werden im Detektorvolumen von IceCube anfangende Ereignisse mit hohen Energien algorithmisch in drei Topologien klassifiziert. Im Datensatz mit einer Lebensdauer von 7.5 Jahren werden zum ersten Mal zwei Doppelkaskaden identifiziert; diese sind Kandidaten für Tau-Neutrinos. Die Eigenschaften der zwei Tau-Neutrino-Kandidaten werden in einer a-posteriori Analyse im Detail studiert. Die statistische Methode wird durch einen Log-Likelihood-Quotienten-Test mit multi-dimensionalen Wahrscheinlichkeitsdichten verbessert. Eine der Doppelkaskaden ist konsistent mit dem Szenario einer misklassifizierten Einzelkaskade, während für die zweite Doppelkaskade die Wahrscheinlichkeit eines nicht-Tau-Neutrino Szenarios auf nur 3% bestimmt wird. Die gemessene Flavor-Zusammensetzung ist konsistent mit der Annahme von astrophysikalischen Neutrinos sowie mit bisher veröffentlichen Resultaten. Die Messung ergibt einen astrophysikalischen Tau-Neutrino Fluss von dPhi / dE=3.0 (-1.8,+2.2) (E / 100TeV)^(-2.87) 10^(-18) GeV^(-1) cm^(-2) s^(-1) sr^(-1), was dem ersten positiven Ergebnis für die Tau-Normalisierung entspricht. Die Nichtexistenz eines astrophysikalischen Tau-Neutrino Flusses wird mit einer Signifikanz von 2.8 sigma abgelehnt. / The IceCube neutrino observatory at the South Pole has confirmed the existence of a diffuse astrophysical neutrino flux. The flavor composition of astrophysical neutrinos carries information on the environments at the sites of cosmic particle acceleration as well as potential imprints of new physics acting during neutrino propagation. To measure the flavor composition the observation of the long-elusive tau neutrinos is required. Starting at an energy of ~O(100 TeV) a tau neutrino charged current interaction can produce a double cascade topology, where the two energy depositions from the tau creation and the tau decay vertices are resolvable. This topology together with the well-established track and single cascade topology is used to measure the flavor composition on Earth. In this work, high-energy events starting in IceCube's detector volume are classified algorithmically into the three topologies. In the dataset with a livetime of 7.5 years, two events are classified as double cascades for the first time, yielding multi-TeV tau-neutrino candidates. The properties of the two tau-neutrino candidates are investigated in an a-posteriori analysis. The statistical method is improved by performing a log-likelihood-ratio test using multi-dimensional probability densities. One of the double cascades is consistent with being a misclassified single cascade, while the second double cascade is found to have a misclassification probability of only 3%. The measured flavor composition nu_e:nu_mu:nu_tau = 0.20:0.39:0.42 is consistent with astrophysical neutrinos and with previously published results. The astrophysical tau-neutrino flux is measured to dPhi / dE=3.0 (-1.8,+2.2) (E / 100TeV)^(-2.87) 10^(-18) GeV^(-1) cm^(-2) s^(-1) sr^(-1) with spectral index gamma=2.87 (-0.20,+0.21), yielding the first non-zero results for the tau normalization. The absence of an astrophysical tau-neutrino flux is disfavored at 2.8 sigma.

Explaining the baryon asymmetry of the Universe has been a long-standing problem of particle physics, with the consensus being that new physics is required as the Standard Model (SM) cannot resolve this issue. Beyond the Standard Model (BSM) scenarios would need to incorporate new sources of \(CP\) violation and either introduce new departures from thermal equilibrium or modify the existing electroweak phase transition. In this thesis, we explore two approaches to baryogenesis, i.e. the generation of this asymmetry. In the first approach, we study the two-particle irreducible (2PI) formalism as a means to investigate non-equilibrium phenomena. After arriving at the renormalised equations of motions (EOMs) to describe the dynamics of a phase transition, we discuss the techniques required to obtain the various counterterms in an on-shell scheme. To this end, we consider three truncations up to two-loop order of the 2PI effective action: the Hartree approximation, the scalar sunset approximation and the fermionic sunset approximation. We then reconsider the renormalisation procedure in an \(\overline{\text{MS}}\) scheme to evaluate the 2PI effective potential for the aforementioned truncations. In the Hartree and the scalar sunset approximations, we obtain analytic expressions for the various counterterms and subsequently calculate the effective potential by piecing together the finite contributions. For the fermionic sunset approximation, we obtain similar equations for the counterterms in terms of divergent parts of loop integrals. However, these integrals cannot be expressed in an analytic form, making it impossible to evaluate the 2PI effective potential with the fermionic contribution. Our main results are thus related to the renormalisation programme in the 2PI formalism: \( (i) \)the procedure to obtain the renormalised EOMs, now including fermions, which serve as the starting point for the transport equations for electroweak baryogenesis and \( (ii) \) the method to obtain the 2PI effective potential in a transparent manner. In the second approach, we study baryogenesis via leptogenesis. Here, an asymmetry in the lepton sector is generated, which is then converted into the baryon asymmetry via the sphaleron process in the SM. We proceed to consider an extension of the SM along the lines of a scotogenic framework. The newly introduced particles are charged odd under a \(\mathbb{Z}_2\) symmetry, and masses for the SM neutrinos are generated radiatively. The \(\mathbb{Z}_2\) symmetry results in the lightest BSM particle being stable, allowing for a suitable dark matter (DM) candidate. Furthermore, the newly introduced heavy Majorana fermionic singlets provide the necessary sources of \(CP\) violation through their Yukawa interactions and their out-of-equilibrium decays produce a lepton asymmetry. This model is constrained from a wide range of observables, such as consistency with neutrino oscillation data, limits on branching ratios of charged lepton flavour violating decays, electroweak observables and obtaining the observed DM relic density. We study leptogenesis in this model in light of the results of a Markov chain Monte Carlo scan, implemented in consideration of the aforementioned constraints. Successful leptogenesis in this model, to account for the baryon asymmetry, then severely constrains the available parameter space. / Die Erklärung der beobachteten Baryon-Asymmetrie im Universum ist ein seit langem ungelöstes Problem in der Hochenergiephysik. Ein weitgehender Konsens besteht darin, dass dafür "neue Physik" erforderlich ist, da dieses Problem nicht im Rahmen des Standardmodells gelöist werden kann. Dazu gehören CP-verletzende Erweiterungen des Standardmodells ebenso wie neue Aspekte des Nichtgleichgewichts und Modifikationen des elektroschwachen Phasenübergangs. In dieser Dissertation werden zwei Herangehensweisen untersucht, mit denen eine Baryon-Asymmetrie erzeugt werden könnte. Die erste Herangehensweise besteht darin, den 2-Teilchen-irreduziblen (2PI) Formalismus anzuwenden, um auf diese Weise Nichtgleichgewichtsphänomene berücksichtigen zu können. Nach Ableitung der renormierten Bewegungsgleichungen, welche die Dynamik des Phasenübergangs beschreiben, werden Methoden diskutiert, mit denen die sogenannten Counterterme im "On-shell"-Schema berechnet werden können. Um dieses Ziel zu erreichen, betrachten wir drei verschiedene Näherungen der 2PI-Wirkung in zweiter Schleifenordnung, nämlich die Hartree- und die skalare 'sunset' Approximation sowie die fermionische 'sunset'-Approximation. Danach kehren wir zur Renormierungsprozedur in einem \(\overline{\text{MS}}\)-Schema zurück, um das effektive 2PI-Potential für die jeweiligen Abschneideverfahren zu berechnen. In den ersten beiden Fällen gelangen wir zu analytischen Ausdrücken für die verschiedenen Counterterme und berechnen anschließend durch Zusammenfügen aller Beiträge das effektive Potential. Im fermionischen Fall erhalten wir ähnliche Gleichungen für die Counterterme, deren Schleifenintegrale allerdings noch divergente Anteile enthalten. Weil diese Integrale nicht in analytisch geschlossener Form dargestellt werden können, ist es in diesem Fall nicht möglich, das effektive Potential zu berechnen. Die beiden wesentlichen Resultate beziehen sich also auf Renormierungsverfahren im 2PI-Formalismus: \( (i) \) eine Methode, um renormierte Bewegungsgleichungen, jetzt auch mit Fermionen, zu erhalten, die als Ausgangspunkt für Transportgleichungen in der elektroschwachen Baryogenese nutzbringend sein können, und \( (ii) \) eine Methode, um das effektive 2PI-Potential in einer transparenten Weise zu bestimmen. Die zweite Herangehensweise befasst sich mit der Baryogenese durch Leptogenese. In diesem Fall wird zunächst eine Asymmetrie im leptonischen Sektor erzeugt, die dann vermittels eines Sphaleron-Prozesses in eine Baryonasymmetrie konvertiert wird. Wiederum betrachten wir eine Erweiterung des Standardmodells im Sinn eines skotogenen Ansatzes. Die zusätzlich eingeführten Teilchen sind ungerade geladen unter einer \(\mathbb{Z}_2\)-Symmetrie und die Massen für die Neutrinos im Standardmodell werden durch Strahlungskorrekturen erzeugt. Wegen der \(\mathbb Z_2\)-Symmetrie sind die leichtesten Teilchen im erweiterten Standardmodell stabil und kommen damit als geeignete Kandidaten für dunkle Materie infrage. Darüber hinaus verursachen die zusätzlich eingeführten schweren Majorana-Singlet-Fermionen durch ihre Yukawa-Wechselwirkung die benötigte CP-Verletzung, wobei Zerfälle im Nichtgleichgewicht zu einer Leptonen-Asymmetrie führen. Dieses Model wird durch eine Vielzahl von Observablen eingeschränkt, wie z.B. Konsistenz mit den Daten zu Neutrino-Oszillationen, Schranken der Verzweigungsverhältnisse für leptonische Flavor-verletzende Zerfälle, elektroschwache Präzisionsobservablen sowie die im Universum beobachtete Dichte dunkler Materie. Wir untersuchen die Leptogenese im Rahmen dieses Modells in einem Parameterraumbereich, der mithilfe einer Makovketten-Monte-Carlo-Simulation die unter Berücksichtigung der genannten Einschränkungen bestimmt wurde. Eine erfolgreiche Leptogenese in diesem Modell, welche auf die gewünschte Baryon-Asymmetrie führt, schränkt dann den Parameterraum erheblich weiter ein.

A measurement of solar neutrinos below 1 MeV of energy will further our knowledge of the neutrino's mass and mixing properties and will provide a probe to possible physics beyond the standard model of particle physics, as well as advance our understanding of energy production in the Sun. Borexino is a liquid scintillator detector that will measure the neutrino energy spectrum to the lowest energy threshold to date. It has been designed to measure the flux of the mono-energetic neutrinos produced by electron capture on 7Be in the Sun's core, which will produce a Compton-like edge in the energy spectrum. Because of the low count rate, Borexino requires extremely low backgrounds, and a good understanding of the backgrounds that do exist. Although the purification techniques used for the scintillator lowered the radioactive contaminates to levels never before achieved, cuts must still be made to the data. At Virginia Tech, we have developed an internal source calibration program that will be able to give us a thorough understanding of both the pulse shape discrimination efficiency and the energy and time response of Borexino. Energy calibration for alphas, betas, and gammas (energy scales) can be accomplished with such sources. When the calibration source is used in conjunction with an accurate source location system any spatial dependencies can be found. The system will use different types of sources at various energies to give the required information to make the cuts needed to extract believable physics from the detector. / Ph. D.

In the upcoming deep underground neutrino experiment (DUNE), Liquid Argon Time Projection Chambers (LArTPCs) will be used as the detector technology, and argon will be used as the nuclear target. In order to reduce the systematic uncertainties on the extracted oscillation parameters, a more precise description of the argon nuclear structure is needed. Electron scattering has been one of the most powerful methods of studying the nuclear structure of a target. Therefore we performed an electron scattering experiment E12-14- 012 in Hall A at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). In the E12-14-012 experiment, we collected data for the inclusive (e,e′) and exclusive (e,e′p) processes for a variety of targets (argon, titanium, aluminum, carbon) at a wide range of kinematics. This thesis presents the measurements of the double differential cross sections for carbon, titanium, aluminum and argon at beam energy E = 2.222 GeV and scattering angle θ = 15.541◦ / Doctor of Philosophy / In the upcoming deep underground neutrino experiment (DUNE), Liquid Argon Time Projection Chambers (LArTPCs) will be used as the detector technology, and argon will be used as the nuclear target. In order to reduce the systematic uncertainties on the extracted oscillation parameters, a more precise description of the argon nuclear structure is needed. Electron scattering has been one of the most powerful methods of studying the nuclear structure of a target. Therefore we performed an electron scattering experiment E12-14- 012 in Hall A at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). In the E12-14-012 experiment, we collected data for the inclusive (e,e′ ) and exclusive (e,e′p) processes for a variety of targets (argon, titanium, aluminum, carbon) at a wide range of kinematics. This thesis presents the measurements of the double differential cross sections for carbon, titanium, aluminum and argon at beam energy E = 2.222 GeV and scattering angle θ = 15.541◦ .

En esta tesis se tratan diferentes aspectos de la acústica presente en un telescopio submarino de neutrinos, principalmente en dos vertientes: en el sistema de posicionamiento acústico utilizado para la monitorización de las posiciones de los módulos ópticos presentes a lo largo del detector, así como en sistemas para detección acústica de neutrinos, técnica que actualmente está en fase de estudio. Todos los estudios realizados están enmarcados dentro de dos colaboraciones europeas para el diseño, construcción y operación de telescopios submarinos de neutrinos: Antares (en fase de operación) y KM3NET (en fase de diseño). Objetivos. Los objetivos de este trabajo pueden resumirse en los siguientes aspectos: - Estudios y análisis del sistema de posicionamiento acústico de Antares. Desarrollo del software para la para la automatización del procesado de los datos de dicho sistema e incorporación de los resultados en la base de datos del experimento. Análisis de los datos proporcionados por dicho sistema con el fin de validar su correcto funcionamiento. - Diseño y desarrollo del sistema de posicionamiento acústico para KM3NeT, telescopio unas 20 veces más grande que Antares. - Estudios para la evaluación de la generación acústica paramétrica para el desarrollo de un calibrador compacto capaz de generar señales tipo neutrino útiles en sistemas de detección acústica. Elementos de la metodología a destacar. Cabe destacar aquí que el trabajo se ha desarrollado en el marco de dos colaboraciones internacionales: ANTARES y KM3NeT, financiados con fondos europeos y nacionales. Por su contexto y el carácter de las actividades realizadas ha sido necesaria la formación en distintos campos: telescopios de neutrinos y astropartículas, pero también en otras áreas como la acústica submarina. Además, se ha desarrollado diversas capacidades y destrezas en diversos ámbitos: en instrumentación, en aplicaciones informáticas, en análisis de datos, etc. Más concretamente, se ha trabajado en aplicaciones informáticas para los desarrollos y análisis en ANTARES. / Bou Cabo, M. (2011). Acoustics for underwater neutrino telescopes [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10989

In this work, we examine how neutrino and collider experiments can each and together put constraints on new physics more stringently than ever. Constraints arise in three ways. First, possible new theoretical frameworks are reviewed and analyzed for the compatibility with collider experiments. We study alternate theories such as the superconnection formalism and non-commutative geometry (NCG) and show how these can be put to test, if any collider excess were to show up. In this case, we use the previous diboson and diphoton statistical excess as examples to do the analysis. Second, we parametrize low energy new physics in the neutrino sector in terms of non-standard interactions (NSI), which are constrained by past and proposed future neutrino experiments. As an example, we show the capability of resolving such NSI with the OscSNS, a detector proposed for Oak Ridge National Lab and derive interesting new constraints on NSI at very low energy (≲ 50 MeV). Apart from this, in order to better understand the NSI matter effect in long baseline experiments such as the future DUNE experiment, we derive a new compact formula to describe the effect analytically, which provides a clear physical picture of our understanding of the NSI matter effect compared to numerical computations. Last, we discuss the possibility of combining neutrino and collider data to get a better understanding of where the new physics is hidden. In particular, we study a model that produces sizable NSI to show how they can be constrained by past collider data, which covers a distinct region of the model parameter space from the DUNE experiment. In combining the two, we show that neutrino experiments are complementary to collider searches in ruling out models such as the ones that utilize a light mediator particle. More general procedures in constructing such models relevant to neutrino experiments are also described. / Ph. D. / As we know, all matter in our daily life is made of particles called atoms and molecules, which are in turn formed by subatomic particles: protons, neutrons, and electrons. If one further divides the former two with certain technology, such as using a proton collider to smash one into another, it goes to the regime of elementary particles. It is shown experimentally that all matter we know is made of elementary particles that cannot be further divided. They include quarks and leptons. Together with the force carrier particles (also called gauge bosons) and the Higgs scalar, they form the Standard Model of particle physics. In this work, we study the properties of elementary particles and the way they interact with each other that are different from the Standard Model predictions. We conduct the research study in the following two aspects: collider phenomena and neutrino phenomena. These two aspects cover the high energy regime of particle scattering process and low energy regime of neutrino propagation, which are two important sectors of great interest recently. As a result of the analysis, we discuss possible ways that the new physics is hidden yet can be detected with next generation experiments.

Doctor of Philosophy / Department of Physics / Glenn A. Horton-Smith / The next generation of nuclear fission reactor based neutrino experiments seeking to measure the Theta-13 mixing angle rely upon measurements made by detectors placed close to the reactor, and therefore less shielded from cosmic ray muons by the earth. 9Li production in liquid scintillator by these cosmic ray muons becomes a serious problem for these experiments that must be dealt with since the 9Li production rate is still a significant fraction of the neutrino interaction rate. This 9Li background reduces the experiment’s sensitivity to measure the Theta-13 mixing angle. This thesis discusses a small detector designed to measure the 9Li production rate in liquid scintillator at the earth’s surface by cosmic ray muons. The detector was designed, built, and finally, calibrated. The ability to find the signals necessary to actually measure the 9Li production rate is shown, establishing that this detector will be able to measure the production rate. A 90% significance level upper limit for the 9Li-like production rate, based on only 3.5 days worth of data, is reported as 213 9Li-like events per day per ton.

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