The cosmic ray neutron method was developed for intermediate-scale soil moisture detection, but may potentially be used for other hydrological applications. The neutron signal of different hydrogen pools is poorly understood and separating them is difficult based on neutron measurements alone. Including neutron transport modeling may accommodate this shortcoming. However, measured and modeled neutrons are not directly comparable. Neither the scale nor energy ranges are equivalent, and the exact neutron energy sensitivity of the detectors is unknown. Here a methodology to enable comparability of the measured and modeled neutrons is presented. The usual cosmic ray soil moisture detector measures moderated neutrons by means of a proportional counter surrounded by plastic, making it sensitive to epithermal neutrons. However, that configuration allows for some thermal neutrons to be measured. The thermal contribution can be removed by surrounding the plastic with a layer of cadmium, which absorbs neutrons with energies below 0.5 eV. Likewise, cadmium shielding of a bare detector allows for estimating the epithermal contribution. First, the cadmium difference method is used to determine the fraction of thermal and epithermal neutrons measured by the bare and plastic-shielded detectors, respectively. The cadmium difference method results in linear correction models for measurements by the two detectors, and has the greatest impact on the neutron intensity measured by the moderated detector at the ground surface. Next, conversion factors are obtained relating measured and modeled neutron intensities. Finally, the methodology is tested by modeling the neutron profiles at an agricultural field site and satisfactory agreement to measurements is found.

This thesis draws upon recent, art historical scholarship in iconography and semiotics to identify and analyze key images in an iconographic program associated with murals, paintings, and posters related to the Austin, Texas music venue, the Armadillo World Headquarters, 1970-1980. Resources include South Austin Museum of Popular Culture, the Center for American History at the University of Texas, Austin, personal communications, and publications concerning the artists, music and history of Austin and the Armadillo World Headquarters. There are five chapters as follows: Introduction, History of the Armadillo World Headquarters, Analysis of the Armadillo Mural and Freddie King Painting, Analysis of Posters for the Grand Opening and the Michael Murphey Cosmic Cowboy Concert, and Conclusion.

Orientador: Ernesto Kemp / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-14T11:18:31Z (GMT). No. of bitstreams: 1 Almeida_RogerioMenezesde_D.pdf: 29880310 bytes, checksum: a6d709505699fa646136930c8822d569 (MD5) Previous issue date: 2009 / Resumo: Quase um século após o descobrimento da radiação cósmica, sua origem, composilção, mecanismos de aceleração e propagação pelo universo são ainda desconhecidos para a faixa de energia ultra-alta (E >~ 10 18 eV). O mistério torna-se ainda maior devido à supressão (corte GZK) no uxo dos raios cósmicos com energias E >~ 6 × 10 19 eV, devido à interação destas partículas com a radiação cósmica de fundo, previsto há cerca de 40 anos. Assim, espera-se que os raios cósmicos com energia acima deste limiar sejam provenientes de fontes distantes em até ~ 200 Mpc. Uma vez que nosso universo local é bastante heterogêneo e a rigidez magnética destas partículas é bastante elevada, espera-se que a distribuição das direções de chegada dos raios cósmicos de energia ultra-alta possa ser correlacionada com as direções de suas fontes, refletindo a anisotropia do universo local. Neste sentido, estudos de anisotropias nas direções de chegadas de tais partículas desempenham papel crucial na investigação da radiação cósmica e compreensão do universo. Este trabalho dedica-se ao estudo de anisotropias de pequena e larga escalas. No primeiro caso, procuramos UHECR¿s correlacionados com o surto gigante de radiação gama emitido pelo SGR 1806-20 em dezembro de 2004. Outro caso estudado é a análise de direções da esfera celeste com excessos de raios gama com significâncias estatísticas maiores que 4s, não associadas a fontes conhecidas, reportadas pela Colaboração JANZOS. Ainda com relação a anisotropias de pequena escala, são estudadas aplicações de filtros de wavelets para detecção de fontes pontuais. No contexto de anisotropias de larga escala, relacionadas a grandes distribuições de matéria, desenvolvemos um método de identificação de anisotropias independente de catálogos de objetos celestes, chamado MIIE. Testamos sua eficiência através de testes de hipóteses e o aplicamos a conjunto de eventos com energia extrema obtidos de dados do Observatório Pierre Auger / Abstract: Almost a century after the discovery of cosmic radiation, their origin, composition, acceleration and propagation mechanisms in the universe is still unknown for the ultra-high energy component ( > ~ 1018 eV). The mystery grows due to the suppression (GZK cutoff) in the ux of cosmic rays with energies E >~ 6 × 10 19 eV, caused by the interaction of these particles and the cosmic microwave background, predicted ~ 40 years ago. Thus, it is expected that cosmic rays with energy above this threshold are produced in sources within ~ 200 Mpc. Since our local universe is very inhomogeneous and the magnetic rigidity of these particles is very high, it is expected that the distribution of the arrival directions of ultra-high energy cosmic rays can be correlated with the directions of their sources, reflecting the anisotropy of our local universe. In this way, anisotropy studies play crucial role in the research of cosmic radiation and understanding of the universe. In this work, small-scale anisotropy, related to the study of point sources, are studied searching for UHECR¿s correlated with the giant are from SGR 1806-20 in December 2004. We have also analized directions with an excess of gamma rays with statistical significance S > 4s, not associated with any known sources, reported by the JANZOS Collaboration. Also, in this thesis wavelets are applied in the detection of point sources. In the context of anisotropy related to large distributions of matter, called large scale anisotropy, we propose a new anisotropy identification method independent of catalogs, so-called MIIE. We test its efficiency through hipothesis tests and apply it to events set obtained from the Pierre Auger data / Doutorado / Física das Particulas Elementares e Campos / Doutor em Ciências

Orientador: Ernesto Kemp / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-27T11:36:07Z (GMT). No. of bitstreams: 1 Nunes_MonicaSoares_M.pdf: 4211832 bytes, checksum: 7414fb6290c92c79d1f11b0fdd3707db (MD5) Previous issue date: 2015 / Resumo: O estudo da radiação cósmica é de extrema importância para a astrofísica. Partículas oriundas de diferentes locais, tanto do sistema solar, quanto fora dele, chegam constantemente à Terra, carregando muitas informações a respeito da sua origem. Quando essas partículas encontram a atmosfera terrestre da-se início a uma cascata de partículas secundárias resultantes da interação do raio cósmico primário com a atmosfera. Dessa chuva de partículas secundárias, os múons são as partículas carregadas mais abundantes que chegam à superfície da Terra. Múons são altamente penetrantes, o que pode representar um problema muito grande em ex- perimentos, mesmo que subterrâneos, de outras partículas. Devido ao seu grande número, eles se tornam extremamente necessários em reconstruções de chuveiros atmosféricos para obtenção de informações a respeito da partícula primária. Tendo conhecimento de suas características, como por exemplo fluxo, ruídos em experimentos podem ser tratados e outros estudos podem ser otimizados. A intensidade de múons na superfície terrestre é bem conhecida como sendo anisotrópica e com uma dependência do ângulo zenital da forma ? (?) = ?0?osn(?). Por simplicidade nos cálculos, este expoente n é freqüentemente utilizado com valor igual a 2, mas estudos mostram que este parâmetro possui dependência com a posição geográfica e com a faixa de energia dos múons em questão. Esta dissertação propõe um método simples para a precisa determinação do expoente n e da intensidade vertical de múons simultaneamente, que pode ser realizado de maneira rá- pida em qualquer laboratório de raios cósmicos, utilizando detectores de partículas, que juntos formam o chamado Telescópio de Múons. Como resultado da aplicação do método no Laboratório de Léptons em Campinas - SP, foi obtido um valor de n de aproximadamente 2.30 e um valor para a intensidade vertical de múons em torno de 146.40? z/m2sr. Dados muito satisfatórios e de acordo com outros experimentos semelhantes já realizados anteriormente no Laboratório. O método também foi aplicado no Fermilab, localizado nos Estados Unidos. Nesta outra loca- lização geográfica, os resultados diferiram bastante dos obtidos em Campinas, com n aproxima- damente 3.66 e intensidade vertical de múons em torno de 158.33 ? zm-2sr-1. O mesmo experimento com o telescópio será realizado em outras posições geográficas afim de se verificar o comportamento do expoente n e da intensidade vertical de múons em diferentes locais / Abstract: The study of cosmic radiation is of utmost importance to astrophysics. Particles from different locations, from inside the solar system, and outside it, constantly arrive on Earth, carrying a lot of information about its origin. When these particles arrives to Earth¿s atmosphere they initiate a cascade of secondary particles resulting from the interaction of the primary cosmic ray with the atmosphere. From this rain of secondary particles, muons are the most abundant charged particles that reach the Earth¿s surface.Muons are highly penetrating, which can be a very big problem in some experiments, even if underground, of other particles. Because of their large number, they become extremely necessary in reconstructions of air showers to obtain information about the primary particle. Having knowledge of its characteristics, such as flux and distribution, noise in some experiments can be treated and other studies can be optimized.Muon intensity in the Earth¿s surface is well known to be anisotropic and has dependence on the zenith angle of ? (?) = ?0 cosn(?). For simplicity in the calculations, this n exponent is often used with a value of 2, but studies show that this parameter has dependence on the geographical position and on the energy range of muons in question. This dissertation proposes a simple method for accurate determination of the exponent n and muon vertical intensity simultaneously, that can be determined quickly in any laboratory cosmic rays using a particle detector, which was called Muon Telescope. As a result of the application of the method on the Leptons Laboratory, in Campinas - SP - Brazil, the value for n that was obtained is about 2.30 and a value for the vertical intensity of muons around 146.40? z/m2sr. This data is very satisfactory and according to similar experiments previously conducted at the Laboratory.This method was applied on Fermilab, located at the United States. On this new geographical location, the results were different from that obtained at Campinas, with n about 3.66 and the vertical intensity around 158.33 ? zm-2sr-1.The same experiment with the telescope will be held in other geographical locations in order to check the n exponent behavior and the muon intensity at different locations / Mestrado / Física / Mestra em Física

Orientadores: Edmilson José Tonelli Manganote, José Augusto Chinellato / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-31T19:37:09Z (GMT). No. of bitstreams: 1 Silva_AndreVieirada_M.pdf: 2116619 bytes, checksum: 5594853aef0531bf0dd2835de169710d (MD5) Previous issue date: 2016 / Resumo: Nesse trabalho, estudamos os processos difrativos nos eventos de interação hadrônica, observados pelos experimentos dos aceleradores HERA, TEVATRON e LHC. Analisamos uma categoria específica de eventos, os chamados eventos C-jatos, observados pela CBJ através exposição de detectores (Câmara de Emulsão Nuclear) à radiação cósmica, no Monte Chacaltaya. Nessa análise foram obtidas as distribuições de multiplicidade e energia em função do ângulo azimutal e a pseudorapidez, a partir dos dados de posição e energia dos eventos C-jatos. Essas distribuições são fundamentais na busca por uma compreensão dos processos de interação que deram origem aos eventos C-jatos. Os resultados da análise mostram as características de uma partícula líder nos eventos C-jatos, numa região frontal em alta pseudorapidez (6 ? ? ? 15) não observada pelos detectores dos aceleradores. Essas características experimentais podem ser indícios a respeito de física difrativa em eventos da radiação cósmica. Em particular, comparamos as distribuições dos eventos C-jatos com as distribuições geradas pelo simulador PYTHIA 8 para processos elásticos e difrativos, na busca por uma caracterização dos eventos C-jatos / Abstract: In this work, we study the diffractive processes in the hadronic interaction events observed by the HERA, TEVATRON and LHC accelerator experiments. We analyzed a specific category of events, the so-called C-jets events, observed by CBJ through exposure of detectors (Nuclear Emulsion Chamber) to cosmic radiation in Mount Chacaltaya. In this analysis the multiplicity and energy distributions were obtained as a function of the azimuth angle and the pseudorapidity, from the position and energy data of the C-jets events. These distributions are fundamental in the search for an understanding of the interaction processes that gave rise to the C-jets events. The results of the analysis show the characteristics of an leading particle in the C-jets events, in a front region in high pseudorapidity (6 ? ? ? 15) not observed by the accelerator detectors. These experimental features may be clues about diffractive physics in events of cosmic radiation. In particular, we compared the distributions of C-jets events with the distributions generated by the PYTHIA 8 simulator for elastic and diffractive processes, in the search for a characterization of C-jets events / Mestrado / Física / Mestre em Física / 165762/2014-4 / CNPQ

abstract: In this dissertation, I present the results from my recent investigations into the interactions involving topological defects, such as magnetic monopoles and strings, that may have been produced in the early universe. I performed numerical studies on the interactions of twisted monopole-antimonopole pairs in the 't Hooft-Polyakov model for a range of values of the scalar to vector mass ratio. Sphaleron solution predicted by Taubes was recovered, and I mapped out its energy and size as functions of parameters. I also looked into the production, and decay modes of $U(1)$ gauge and global strings. I demonstrated that strings can be produced upon evolution of gauge wavepackets defined within a certain region of parameter space. The numerical exploration of the decay modes of cosmic string loops led to the conclusions that string loops emit particle radiation primarily due to kink collisions, and that their decay time due to these losses is proportional to $L^p$, where $L$ is the loop length and $p \approx 2$. In contrast, the decay time due to gravitational radiation scales in proportion to $L$, and I concluded that particle emission is the primary energy loss mechanism for loops smaller than a critical length scale, while gravitational losses dominate for larger loops. In addition, I analyzed the decay of cosmic global string loops due to radiation of Goldstone bosons and massive scalar ($\chi$) particles. The length of loops I studied ranges from 200-1000 times the width of the string core. I found that the lifetime of a loop is approximately $1.4L$. The energy spectrum of Goldstone boson radiation has a $k^{-1}$ fall off, where $k$ is the wavenumber, and a sharp peak at $k\approx m_\chi/2$, where $m_\chi$ is the mass of $\chi$. The latter is a new feature and implies a peak at high energies (MeV-GeV) in the cosmological distribution of QCD axions. / Dissertation/Thesis / Doctoral Dissertation Physics 2020

Le fond diffus cosmologique (CMB) permet d'étudier la physique à l'oeuvre dans l'univers primordial.Ses anisotropies ont été mesurées récemment avec une haute précision par le satellite Planck. Ces mesures sont en accord avec les prédictions de l'inflation, la théorie décrivant une période d'expansion rapide et accélérée de l'univers primordial. Pour distinguer les différents modèles d'inflation, il est important de chercher des déviations de la distribution gaussienne des anisotropies du CMB, appelées non-gaussianités.Cette thèse est consacrée à l'étude, à la fois des points de vue observationnels et théoriques, des non-gaussianités du type bispectral (liées aux fonctions de corrélations à trois points), caractérisées par les paramètres d'amplitude fNL.Après une partie introductive sur le modèle standard de la cosmologie et la théorie des perturbations cosmologiques,la deuxième partie de ce manuscrit décrit la méthode de l'estimateur de bispectre binné, utilisée pour extraire de l'information sur les non-gaussianités à partir des mesures du CMB. Pour obtenir des informations sur l'univers primordial, les données doivent être nettoyées de la contamination dûe aux avant-plans galactiques. Nous vérifions les résultats au niveau du bispectre. Des modèles numériques de plusieurs avant-plans galactiques sont déterminés à partir des données de Planck. Ces modèles ont été utilisés dans des analyses des cartes de la température du CMB et du ciel brut, afin d'améliorer la détermination de la quantité de non-gaussianités primordiales.La troisième partie de ce manuscrit porte sur l'étude des non-gaussianités bispectrales produites dans des modèles d'inflation à deux champs avec des termes cinétiques standards. Il est important de mieux comprendre quelles régions de l'espace des modèles d'inflation ont été éliminées par les résultats de Planck.Nous appliquons une nouvelle expression de fNL au cas d'un potentiel somme et nous montrons qu'il est très difficile de satisfaire en même temps aux conditions permettant fNL grand et la contrainte observationnelle sur l'indice spectral ns. Pour le cas de la somme de deux potentiels monomiaux et d'une constante, nous montrons explicitement dans quelles régions de l'espace des paramètres cela est possible et comment construire un tel modèle. Finalement, nous utilisons la nouvelle expression pour fNL pour montrer que dans le cas du potentiel somme, les résultats analytiques restent valides au-delà de l'approximation de roulement lent. / A powerful probe of the physics at play in the early universe is the Cosmic Microwave Background(CMB). Its anisotropies have been measured recently with high precision by the Planck satellite. These measurements are in agreement with the predictions of inflation, a theory describing a period of fast and accelerated expansion in the early universe. To discriminate between the different inflation models, it is important to look for deviations from Gaussianity of the CMB anisotropies (i.e. non-Gaussianity). This thesis is devoted to the study of non-Gaussianity of the bispectral type (related to the three-point correlation functions) parametrized by its amplitude parameters fNL, both from the theoretical and observational points of view.After an introductory part on standard cosmology, the second part of the thesis describes the method of the binned bispectrum estimator, used to extract information about non-Gaussianity from CMB measurements.In order to recover information about the primordial universe, one has to clean observational data from the contamination caused by galactic foregrounds. We verify the results at the bispectral level. Numerical templates for the temperature bispectra of several galactic foregrounds are determined using data from the 2015 Planck release. These templates are then used to perform joint analyses on raw sky and CMB temperature data maps, to improve the determination of the amount of primordial non-Gaussianity. In the third part, the level of bispectral non-Gaussianity produced in two-field inflation models with standard kinetic terms is investigated using the long-wavelength formalism. It is important to better understand what regions of inflation model space have been ruled out by Planck. We apply a newly derived expression for fNL to the case of a sum potential and show that it is very difficult to satisfy simultaneously the conditions for a large fNL and the observational constraints on the spectral index ns. In the case of the sum of two monomial potentials and a constant we explicitly show in which small region of parameter space this is possible, and we show how to construct such a model. Finally, we also use the new expression for fNL to show that for the sum potential,the explicit expressions remain valid even beyond the slow-roll approximation.

Les simulations, de plus en plus, sont capables de saisir la complexité de l'époque de réionisation, durant laquelle l'hydrogène neutre de l'Univers a été ionisé par les premières sources lumineuses. Des bases de données représentatives de la multitude de signaux possibles seront nécessaires pour contraindre les paramètres des modèles quand des observations 21~cm seront disponibles. À cette fin, et en préparation des observations à venir sur des instruments comme SKA, nous avons développé une base de données de cones de lumières EoR haute-résolution (21ssd.obspm.fr), ainsi qu'une modélisation du bruit thermique. Nous avons également développé un formalisme permettant de quantifier la différence entre les modèles de cette base de données, en utilisant le spectre de puissance et la fonction de distribution des pixels. Nous trouvons que les deux diagnostiques sont sensibles à des paramètres différents des modèles, ce qui signifie que les deux peuvent être utilisés ensemble de manière complémentaire pour extraire l'information maximale. De plus, en utilisant le code 21cmFAST, nous avons développé des stratégies pour échantillonner l'espace des paramètres d'une manière optimale (plus homogène et isotrope), afin de fournir le meilleur point de départ entrainer un réseau de neurones. Ce réseau retrouve les paramètres du modèle en se basant sur une observable. Nous observons une amélioration modérée dans la précision de ses prédictions quand nous utilisons l'échantillonnage optimisé lors de son entrainement. / Simulations are increasingly able to capture the intricacies of the Epoch of Reionization, during which the neutral hydrogen in the Universe was ionized by the first luminous sources. Databases encompassing the range of possible signals will be needed to constrain parameter values when 21~cm observations are available. In preparation for upcoming experiments such as the SKA, we have developed a database of high-resolution EoR lightcones (21ssd.obspm.fr), along with realistic thermal noise modelling. We examine frameworks with which we can quantify the difference between entries in this database, specifically with the power spectrum and pixel distribution function. We find that the two diagnostics are sensitive to different parameters, meaning they can be used together to extract maximumal information. Then, using the 21cmFAST code, we explore how to optimally sample a parameter space (so that it is more homogeneous and isotropic), in order to provide the best set-up for parameter extraction. Finally, the improved sampling is used in training a neural network. The neural network uses observables as input data, and attempts to estimate the corresponding parameter values. When the optimal sampling is used as training data, we find that the neural network is able to estimate parameter values with a modest improvement in accuracy.

La compréhension des premiers instants de notre Univers complèterait notre description de son histoire et permettrait également une exploration de la physique fondamentale à des échelles d'énergie jusque là inatteignables. L'inflation cosmique est le scénario privilégié pour décrire ces premiers instants car il s'intègre très bien dans le modèle standard de la cosmologie. Selon ce scénario l'Univers aurait connu une courte période d'expansion accélérée peu après le Big Bang. Quelques indices favorisent ce modèle cependant toujours en attente d'une signature observationnelle décisive. Les modes B du fond diffus comologique (FDC) aux grandes échelles angulaires sont générés par les ondes gravitationnelles primordiales, produites durant l'inflation cosmique. Dans ce cadre, la détection des modes B primordiaux est le but de nombreuses expériences, actuelles ou à venir. Cependant, des effets astrophysiques et instrumentaux rendent sa détection difficile. Plus précisément, une couverture incomplète de la polarisation du FDC (inhérente à toute observation du FDC) entraine la fuite des modes E dans B, un problème majeur dans l'estimation des modes B. Cet effet peut empêcher une détection des modes B même à partir de cartes parfaitement nettoyées, car les modes E fuyant (beaucoup plus intenses) masquent les modes B. Diverses méthodes offrant une estimation de modes B théoriquement non affectés par cette fuite, ont été récemment proposées dans la littérature. Cependant, lorsqu'elles sont appliquées à des expériences réalistes, elles ne corrigent plus exactement cette fuite. Ces méthodes doivent donc être validées dans le cadre d'expériences réalistes. Dans ce but, j'ai travaillé sur l'implémentation et le développement numérique de trois méthodes typiques de pseudospectres. Ensuite, je les ai testé dans le cas de deux expériences fiducielles, typiques d'une expérience suborbitale et d'une potentielle mission satellite. J'ai alors montré l'efficacité et la nécessité d'une méthode en particulier: la méthode dite pure. J'ai également montré que le cas d'une couverture quasi complète du ciel n'est pas trivial, à cause des contours compliqués du masque galactique et des points sources. Par conséquent, une estimation optimale de pseudospectre des modes B exige l'utilisation d'une telle méthode également dans le contexte d'une mission satellite. Grâce à cette méthode, j'ai fait des prévisions réalistes sur les contraintes qu'une détection de la polarisation du FDC pourra apporter sur la physique de l'Univers primordial. J'ai tout d'abord étudié la détectabilité du rapport tenseur-sur-scalaire r qui quantifie l'amplitude des ondes gravitationnelles primordiales, directement relié à l'échelle d'énergie de l'inflation, dans le cas de différentes expériences dédiées à la détection de la polarisation du FDC. J'ai montré qu'une mission satellite nous permettrait de mesurer un rapport tenseur-sur-scalaire de l'ordre de 0.001, autorisant une distinction entre les modèles d'inflation à champ fort et faible. De plus, dans le cas d'une extension du modèle standard de la cosmologie, des corrélations EB et TB du FDC peuvent être générées. En particulier, j'ai prévu les contraintes que nous pourrons mettre sur une violation de parité durant l'univers primordial à partir d'observations sur une grande ou une petite partie du ciel. Mes résultats ont montré qu'une expérience satellite est nécessaire pour mettre des contraintes sur une gamme de modèles de violation de parité. J'ai finalement abordé la problématique de la détectabilité d'une signature observationnelle d'un champ magnétique primordial. / A deep understanding of the first instants of the Universe would not only complete our description of the cosmic history but also enable an exploration of new fundamental phsyics at energy scales unexplored on Earth laboratories and colliders. The most favoured scenario which describes these first instants is the cosmic inflation, an ephemeral period of accelerated expansion shortly after the big bang. Some hints are in favour of this scenario which is however still waiting for a smoking-gun observational signature. The cosmic microwave background (CMB) B modes would be generated at large angular scales by primordial gravitational waves produced during the cosmic inflation. In this frame, the primordial CMB B modes are the aim of various ongoing or being-deployed experiments, as well as being-planned satellite mission. However, unavoidable instrumental and astrophysical features makes its detection difficult. More specifically, a partial sky coverage of the CMB polarisation (inherent to any CMB measurements) leads to the E-to-B leakage, a major issue on the estimation of the CMB B modes power spectrum. This effect can prevent from a detection of the primordial B modes even if the polarisation maps are perfectly cleaned, since the (much more intense) leaked E-modes mask the B-modes. Various methods have been proposed in the literature offering a B modes estimation theoretically free from any leakage. However, when applied to real data, they are no longer completely leakage-free and remove part of the information on B-modes. These methods consequently need to be validate in the frame of real data analysis. In this purpose, I have worked on the implementation and numerical developments of three typical pseudospectrum methods. Afterwards, I have tested each of them in the case of two fiducial experimental set ups, typical of current balloon-borne or ground based experiments and of potential satellite mission. I have therefore stated on the efficiency and necessity of one of them: the so-called pure method. I have also shown that the case of nearly full sky coverage is not trivial because of the intricate shape of the contours of the point-sources and galactic mask. As a result this method is also required for an optimal B modes pseudospectrum estimation in the context of a satellite mission. With this powerful method, I performed realistic forecasts on the constraints that a CMB polarisation detection could set on the physics of the primordial universe. First of all, I have studied the detectability of the tensor-to-scalar ratio r, amounting the amplitude of primordial gravity waves and directly related to the energy scale of inflation, in the case of current suborbital experiments, a potential array of telescopes and a potential satellite mission. I have shown that a satellite-like experiment dedicated to the CMB polarisation detection will enable us to measure a tensor-to-scalar ratio of about 0.001, thus allowing for distinguishing between large and small field models of inflation. Moreover, in extension of the standard model of cosmology, the CMB EB and TB correlations can be generated. In particular, I have forecast the constraints that one could set on a parity violation in the gravitational waves during the primordial universe from observations on a small and a large part of the sky. Our results have shown that a satellite-like experiment is mandatory to set constraints on a range of parity violation models. I finally address the problematic of the detectability of observational signature of a primordial magnetic field.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22245号 / 理博第4559号 / 新制||理||1655(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 田中 貴浩, 教授 川合 光, 教授 向山 信治 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM