La production du boson de Higgs associée à une paire de quarks top est l'un des modes de production de boson de Higgs les plus importants bien que toujours pas encore observé. Par conséquent, sa découverte est l'une des recherches les plus ambitieuse après la découverte Higgs: non seulement cela sera la première fois que nous pourrons observer ce mode de production du Higgs mais nous pourrons également en mesurer le couplage de Yukawa au quark top. Les résultats de ces mesures peuvent répondre aux questions fondamentales du Modèle Standard (MS) et peuvent également donner des indices de nouvelle physique au-delà du MS. Une analyse de la recherche de la production de boson de Higgs associée à une paire de quarks top dans des états finaux à trois leptons est présentée dans cette thèse. Cette analyse est réalisée avec des données collectées par le détecteur ATLAS en 2015 et 2016 pendant la campagne dite « Run 2 » et correspondant à une luminosité intégrée de 36.1 fb-1 à une énergie dans le centre de masse de 13 TeV. Elle utilise un algorithme d'arbre de décision renforcé pour discriminer le signal et le fond. Le bruit de fond dominant de faux leptons est estimé avec une méthode de matrice s’appuyant sur les données (Méthode de la Matrix). Pour un Higgs standard de 125 GeV, un excès d'événements par rapport au bruit de fond attendu d'autres processus MS est trouvé avec une signification observée de 2.2 écarts-types, comparé à une prédiction de 1.5 écart-type. Le meilleur ajustement pour la section efficace de production $t\bar tH$ est de $1.5^{+0.8}_{-0.7}$ fois l'espérance SM, consistant avec la valeur SM du couplage de Yukawa au quark top. / The production of the Higgs boson associated with a pair of top quarks is one of the most important Higgs boson production modes yet still not observed. Therefore, its discovery is one of the most challenging searches after the Higgs discovery: not only will it be the first time we can observe this Higgs production mode but also we will be able to measure its Yukawa coupling to the top quark. The measured results can answer the basic question of the Standard Model (SM) and can also search for any hints of new physics beyond the SM prediction. An analysis searching for the production of the Higgs boson associated with a pair of top quarks in three leptons final states is presented in this thesis. It is performed with the data collected by the ATLAS detector in 2015 and 2016 during the so-called « Run 2 » campaign corresponding to an integrated luminosity of 36.1 fb−1 at a center of mass energy of 13 TeV. It uses a boosted decision tree algorithm to discriminate between signal and background. The dominant background of fake leptons is estimated with the data-driven matrix method (Matrix Method). For a 125 GeV Standard Model Higgs boson, an excess of events over the expected background from other SM processes is found with an observed significance of 2.2 standard deviations, compared to an expectation of 1.5 standard deviations. The best fit for the $t\bar tH$ production cross section is $1.5^{+0.8}_{-0.7}$ times the SM expectation, consistent with the SM value of the Yukawa coupling to top quarks.

No description available.

The box corer is a relatively new tool used in the geotechnical community for collection of soft seabed sediments. Miniature full flow and model pipeline probes were developed as tools to characterize and obtain soil parameters of soft seabed sediments collected in the box core for design of offshore pipelines and analysis of shallow debris flows. Probes specifically developed for this study include the miniature t-bar, ball, motorized vane (MV), and toroid. The t-bar, ball, and MV were developed to measure intact and remolded undrained shear strengths (su and sur). The t-bar and ball can obtain continuous strength profiles and measure sur at discrete depths in the box corer while the MV measures su and sur at discrete depths. The toroid is a form of model pipeline testing which was developed to investigate pipe-soil interaction during axial pipeline movement. Vertical loading and displacement rates can be selected for the toroid to mimic axial pipeline displacement for a variety of pipe weights. A load frame for both miniature penetrometer and toroid testing was developed for testing directly on box core samples offshore. This research presents results from offshore and laboratory testing of the box core and recommended testing procedures for full flow and toroid probes on box core samples.

Magíster en Gestión para la Globalización / En este manuscrito se analiza y evalúa el establecimiento y operación de un Teahouse de estilo contemporáneo en Santiago de Chile emulando el modelo de negocios de la cadena de Teahouse Australiana "T2" (www.t2tea.com). El mercado de los Teahouse en Santiago de Chile es nuevo, por tanto su propuesta de valor coincide con la ventaja de T-Bar como primer jugador en este nicho, aportando con variedad, sofisticación y exclusividad como factores diferenciadores que lo distingan de sus posibles rivales en el mercado. En cuanto a la metodología utilizada, se optó por la proyección clásica para un plan de negocios, consistente en tres etapas: a) Estudio y análisis de mercado del té en Chile. b) Estudio del rubro de servicios en donde se pretende establecer el proyecto. c) Proyección financiera del proyecto. Luego del análisis financiero del proyecto, nos encontramos frente a una posibilidad cierta de implementación de un nuevo tipo de negocio en Chile. Los resultados de margen bruto sobre ventas de un 80% y el comienzo de ganancias en el balance general proyectado a partir del segundo mes de operaciones auguran un buen comienzo. Se concluye de esta forma que T-Bar es un negocio con futuro, de fácil implementación y operación. La potencialidad de fortalecer la marca y crear la franquicia T-Bar son incentivos para inversionistas que quieran apostar por este proyecto.

This thesis presents a search for resonant production of top-antitop quark pairs in final states containing at least one electron or muon. A number of beyond the standard model (BSM) theories incorporate a specific role for the top quark, resulting in resonances that preferentially decay to t(bar over t) pairs. The data sample analysed corresponds to an integrated luminosity of 2.05 fb^-1 recorded during 2011 using the ATLAS detector at the Large Hadron Collider. The proton-proton centre-of-mass energy was 7 TeV. The search is tailored towards heavy resonances at the TeV-scale which therefore decay to top quarks with high transverse momentum. Large hadronic jets are used to reconstruct the energy carried by the hadrons and the substructure of these jets is studied in order to identify hadronically decaying top quarks. The reconstruction can therefore proceed even if the decay products of the top quark are highly collimated. This study represents the first use of jet substructure techniques in a search for t(bar over t) resonances using hadron-hadron collision data. The invariant mass of the reconstructed t(bar over t) pair is used to test compatibility of the data with the standard model prediction. No evidence for t(bar over t) resonances is found. Upper limits are derived on the production cross-section times branching ratio for narrow and wide resonant states, at the 95 % credibility level. An upper limit of 0.61 (0.65) pb is set for a narrow (wide) resonance with a mass of 1 TeV. Two specific BSM models are excluded within certain mass ranges: the narrow leptophobic Z' boson with mass 600 - 1150 GeV and the wide Kaluza-Klein gluon with a mass below 1.5 TeV. These results represent a significant improvement on those of previous searches performed at the ATLAS experiment, which did not use jet substructure techniques. In addition, the possibility of using jets which decrease in size as their transverse momentum increases is investigated using simulated data. The yield of events due to resonant t(bar over t) production increases by approximately 20 % compared to when using jets of fixed size. Furthermore, the resolution of the invariant mass of the reconstructed t(bar over t) pair is found to improve by almost one fifth. It is recommended that a calibration scheme be developed for these variable-sized jets, so that their potential to improve the sensitivity to t(bar over t) resonances can be investigated further.

[Truncated abstract] This research has studied the penetration and extraction resistance profiles of different types of penetrometers in soft clay. The penetrometers of interest include the cone, T–bar, ball and plate. Effects of the surface roughness and aspect ratio of the T–bar penetrometer on its resistance have also been investigated. Undrained shear strength, Su, profiles derived from the penetration tests are compared with the shear strengths measured from field vane shear tests and laboratory (triaxial and simple shear) tests. Both in situ and centrifuge model penetration tests were undertaken for the research. In addition, ‘undisturbed’? tube samples were retrieved from both the field and the centrifuge strongbox samples (after completion of the centrifuge tests) for laboratory testing. The in situ testing was carried out in Western Australia, at the Burswood site near Perth, with tests including cone, T–bar, ball and plate penetrometer tests, and vane shear tests. Interestingly, the T–bar, ball and plate (‘full-flow’) penetrometers showed a narrow band of resistance profiles both during penetration and extraction, with a range of around 15 % between the highest and lowest profiles and standard deviation of 15 %. However, the cone penetrometer gave similar resistance at shallow depths but increasingly higher penetration resistance at depths greater than 7 m – a phenomenon that is also common in offshore results. During extraction, the cone penetrometer gave a higher resistance profile than the full–flow penetrometers for much of the depth of interest. The Su profile measured directly from the vane shear tests falls within the Su profiles derived from the penetration resistances of the full–flow penetrometers, using a single bearing factor, N = 10.5 (the value originally suggested in the literature for a T–bar penetration test). Again, the cone penetrometer demonstrated diverging results, requiring two separate values for the cone factor, Nkt (10.5 initially increasing to 13 for depths below 10 m) in order to give Su similar to the vane shear tests. This highlights the possible variability of the cone factor with depth. Cyclic penetration and extraction tests were performed at specific depths for each fullflow penetrometer. These tests comprised displacement cycles of ±0.5 m about the relevant depth, recording the penetration and extraction resistances over five full cycles. The results may be used to derive the remoulded strength and sensitivity of the soil. Laboratory tests such as triaxial and simple shear tests were performed on ‘undisturbed’ tube samples retrieved from the same site to evaluate the in situ shear strengths in the laboratory. However, the resulting Su data were rather scattered, much of which may be attributed to variable sample quality due to the presence of frequent shell fragments and occasional silt lenses within the test samples. In general, N factors for the full–low penetrometers, back–calculated using Su values measured from the simple shear tests, fell mainly in a range between 9.7 and 12.8 (between 10.4 and 12.2 for the standard size T–bar (250 mm x 40 mm))