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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Gewinnung und Charakterisierung von humanen Zementoblasten / Sourcing and characterisation of human cementoblasts

Bernhardt, Katharina 14 May 2018 (has links)
No description available.
102

Measurement of the mixing parameters of neutral charm mesons and search for indirect CP violation with D⁰ → K⁰_sπ⁺π⁻ decays at LHCb

Reichert, Stefanie January 2016 (has links)
The hadronic decay D0 → KS pi+ pi- provides direct access to the measurement of the mixing parameters of the neutral charm meson system and allows to test for indirect CP violation. Mixing is a time-dependent phenomenon for which the time evolution of the transition amplitude of a D0 (anti-D0) decay to the final state KS pi+ pi- has to be considered. The parameters driving those time-dependent oscillations are x and y, depending on the masses and widths of the physical eigenstates. The CP violation parameters |q/p| and phi describe the superposition of the flavour eigenstates D0 and anti-D0 and of the physical eigenstates D1 and D2. By measuring the time- and phase-space dependent distribution of D0 → KS pi+ pi- decays, the mixing parameters can be extracted and a search for indirect CP violation can be performed. This thesis reports a measurement of the mixing parameters and the preparations of a measurement of the CP violation parameters on data collected with the LHCb experiment in 2011 and 2012, corresponding to an integrated luminosity of 3/fb. The D0 and anti-D0 mesons are required to originate from a semileptonic decay of a B meson. The parameters of interest are extracted from a fit in D0 decay time and the Dalitz variables. The phase-space distribution of D0 → KS pi+ pi- decays is modelled by expressing the three-body decay as a succession of two-body decays. The decay amplitude of a D0 or anti-D0 meson into KS pi+ pi- final state is a superposition of all possible intermediate resonances and the single resonances interfere with each other across the phase-space.
103

Search for CP violation in [Tau] decays at BABAR

Choi, Hervé Hiu Fai 15 November 2011 (has links)
According to the Big Bang Theory, matter and antimatter were produced in equal amounts at the beginning. Over time the antimatter disappeared, leaving galactic struc- tures composed only of matter. Therefore, there is some process in nature that proceeds at different rates for matter and antimatter due to the violation of the CP symmetry. CP violation has been observed in strange and bottom quark meson decays. However, a direct CP violation is predicted in the τ lepton sector. Specifically, the charge asymmetry due to CP violation in the decay τ − → π−K0S (≥ 0π0) ντ is predicted to be (+0.33 ± 0.01)%. In this work the charge asymmetry of the decay τ − → π−K0S (≥ 0π0) ντ is measured using a dataset of 437 million τ lepton pairs collected by the BABAR experiment at the SLAC Na- tional Accelerator Laboratory. The charge asymmetry induced by CP violation is found to be A = (−0.45 ± 0.24 ± 0.11) %, consistent with prediction. / Graduate
104

Geometric aspects of gauge and spacetime symmetries

Gielen, Steffen C. M. January 2011 (has links)
We investigate several problems in relativity and particle physics where symmetries play a central role; in all cases geometric properties of Lie groups and their quotients are related to physical effects. The first part is concerned with symmetries in gravity. We apply the theory of Lie group deformations to isometry groups of exact solutions in general relativity, relating the algebraic properties of these groups to physical properties of the spacetimes. We then make group deformation local, generalising deformed special relativity (DSR) by describing gravity as a gauge theory of the de Sitter group. We find that in our construction Minkowski space has a connection with torsion; physical effects of torsion seem to rule out the proposed framework as a viable theory. A third chapter discusses a formulation of gravity as a topological BF theory with added linear constraints that reduce the symmetries of the topological theory to those of general relativity. We discretise our constructions and compare to a similar construction by Plebanski which uses quadratic constraints. In the second part we study CP violation in the electroweak sector of the standard model and certain extensions of it. We quantify fine-tuning in the observed magnitude of CP violation by determining a natural measure on the space of CKM matrices, a double quotient of SU(3), introducing different possible choices and comparing their predictions for CP violation. While one generically faces a fine-tuning problem, in the standard model the problem is removed by a measure that incorporates the observed quark masses, which suggests a close relation between a mass hierarchy and suppression of CP violation. Going beyond the standard model by adding a left-right symmetry spoils the result, leaving us to conclude that such additional symmetries appear less natural.
105

Teorias efetivas e violação de sabor leptônico em decaimentos do Higgs /

Prado, Leônidas Augusto Fernandes do. January 2015 (has links)
Orientador: Ricardo D'Elia Matheus / Banca: Oscar José Pinto Eboli / Banca: Rogério Rosenfeld / Resumo: Consideramos o decaimento do Higgs violando sabor leptônico h→ 'tau' 'mü' no contexto de teorias efetivas. O CMS divulgou recentemente um excesso de eventos de 2,5 'sigma' neste canal. O operador responsável por este processo, no entanto, está em muitos casos correlacionado com operadores de dipolo, que já têm fortes restrições experimentais. Exploramos então em que casos é possível de se obter um operador de violação de sabor grande o suficiente para ser visto em decaimentos do Higgs no LHC, porém ainda respeitando os limites encontrados em decaimentos radiativos de léptons. Apresentamos também dois modelos, um do tipo Higgs Composto e outro do tipo Higgs Portal, mostrando como o processo h→ 'tau' 'mü' surge em cada um deles. Caso o sinal do CMS seja confirmado, o segundo modelo será favorecido, enquanto é improvável que o primeiro consiga o explicar / Abstract: We consider the Higgs Lepton Flavor Violating decay h→ 'tau' 'mü' in the framework of effective theories, on which CMS reported a 2.5 σ excess of events. The operator that is responsible for this process, however, is in many models correlated to dipole operators that are already under stringent experimental constraints. We then explore in which cases it is possible to obtain a flavor violating operator that is big enough to be seen in Higgs decays at the LHC, while still respecting the leptonic radiative decay bounds. We also present two models, a simplified Composite Higgs model and a Higgs Portal model, showing how the process h→ 'tau' 'mü' is generated in each of them. We find that if the CMS signal is confirmed, the second model is favored, while it is unlikely that the first model will be able to explain it / Mestre
106

Modeling and Charging Control of a Lithium Ion Battery System for Solar Panels

Heinen, Garrett David 01 June 2017 (has links)
The advancement in solar panel and battery technology makes them useful for energy supply and storage. This thesis involves the modeling and charging control of a lithium ion battery system for solar panels. The proposed model is based on the parameters and characteristics of a realistic battery and solar panel system; and the hybrid control approach combines the advantages of the adaptive incremental conductance method and the perturb and observe method to track the maximum power point of the solar panel for charging the battery unit. Computer simulation results demonstrate that this proposed approach offers a faster convergence rate than the adaptive incremental conductance method, and less steady-state error than the perturb and observe method.
107

Mesure du rapport d'embranchement et du facteur de forme de la désintégration B⁰ → π⁻l⁺v, et détermination de |V[indice]u[indice]b| avec une technique de reconstruction relâchée du neutrino

Côté, David January 2007 (has links)
No description available.
108

Observation of νμ→νe oscillation in the T2K experiment / T2K実験におけるνμ→νe振動の観測

Ieki, Kei 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18063号 / 理博第3941号 / 新制||理||1568(附属図書館) / 30921 / 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 市川 温子, 教授 鶴 剛 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
109

Corporal Punishment, Attachment, and Alcohol-Related Outcomes among College Students

Gangemi, Bernadine M. 24 September 2020 (has links)
No description available.
110

Tests des modèles de la leptogenèse par la mesure de la violation CP leptonique au LHC

Sanfaçon, Nicolas 09 December 2022 (has links)
Plusieurs observations montrent une asymétrie baryons-antibaryons dans l'Univers. La principale théorie expliquant cette asymétrie est la baryogenèse qui requiert les trois conditions de Sakharov : la non-conservation du nombre baryonique, la présence de violation CP et des interactions entre particules hors de l'équilibre thermique. La baryogenèse nécessite de considérer de la physique au-delà du Modèle Standard (MS), car le MS suppose généralement une asymétrie baryonique trop petite. La baryogenèse peut être obtenue à partir de la leptogenèse, la théorie équivalente pour les leptons. De nouvelles particules et interactions impliquant des leptons généreraient une asymétrie leptonique (AL) mesurable au LHC qui serait transférable au secteur baryonique. L'ajout de neutrinos de chiralité droite (RH) au MS est un choix naturel pour expliquer l'origine de la masse des neutrinos et l'existence d'une AL, et donc d'une asymétrie baryonique. Le projet aborde certains processus détectables au LHC impliquant la désintégration de bosons W en neutrinos RH. Ces processus peuvent violer le nombre leptonique et la symétrie CP. Des facteurs d'asymétrie CP sont calculés et permettent de mesurer des invariants CP. Les invariants CP dépendent des paramètres du modèle et quantifient la violation CP. Ces invariants CP apparaissent dans les équations de Boltzmann qui décrivent l'évolution de l'AL. La résolution de ces équations permet de calculer le ratio du nombre de baryons sur le nombre de photons dans l'Univers. L'identification des invariants CP qui décrivent l'AL permet de tester les modèles de la leptogenèse par la mesure de processus impliquant de la violation CP au LHC. Pour répondre à ces objectifs, un scénario de leptogenèse résonante a été testé. Les résultats obtenus montrent que les invariants CP nécessaires pour reproduire l'asymétrie baryonique sont trop petits pour être mesurés au LHC. De futures recherches pourraient s'intéresser à d'autres modèles menant à un signal observable au LHC.

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