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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.
31

Estudo da produção de estranheza em colisões entre íons pesados relativísticos a & / Measurements of Strangeness Production at 62.4 GeV

Karin Silvia Franzoni Fornazier Guimarães 28 September 2007 (has links)
O principal objetivo deste trabalho foi obter a produção das partículas estranhas K0, e em colisões entre íons pesados relativísticos para ÖsNN = 62.4 GeV, bem como estudar o comportamento sistemático dessa produção em função da energia. Para isso, utilizamos os dados provenientes da colisão de íons pesados relativísticos obtidos pelo experimento STAR do RHIC. O objetivo deste trabalho também foi o de estudar dois estágios específicos da evolução do fireball formado nessas colisões: os chamados freeze-out químico e térmico. Estes estágios (ou fases) foram estudadas a partir das razões entre diversas partículas e da distribuição de momento transversal das mesmas, comparando os resultados com previsões e ajustes de modelos térmicos, a fim de avaliar possíveis efeitos da formação de um Plasma de Quarks e Gluons (QGP) em equilíbrio térmico sobre os hádrons medidos pelo experimento. O freeze-out químico foi estudado a partir das razões entre abundâncias de partículas produzidas na colisão, que foram comparadas a ajustes de um modelo térmico que trata o fireball como um gás de hádrons em equilíbrio (THERMUS) e aos resultados de um modelo que não assume esse equilíbrio (SHM). Com essa abordagem, verificamos que o modelo THERMUS ajusta bem os dados experimentais para uma ampla faixa de energias de colisão, principalmente para 62.4 GeV. Os parâmetros termodinâmicos obtidos foram estudados em função da energia para verificarmos se há um comportamento suave do sistema ou mudanças abruptas. O estudo indicou que esse comportamento é suave com a energia. Ainda neste estudo do freeze-out químico, comparamos os resultados do modelo THERMUS com os resultados do modelo que considera o não ? equilíbrio químico, o SHM. Nesta comparação, a razão apresentou um comportamento interessante, sugerindo que a energias mais baixas o sistema se comporta conforme a prescrição do modelo SHM, enquanto que o modelo que considera o fireball como um gás de hádrons em equilíbrio, novamente, demonstrou melhor compatibilidade a energias mais altas, reafirmando aqui a indicação de uma possível formação de um sistema termalizado. O freeze-out cinético/térmico foi estudado com os espectros de momento transversal, considerando um modelo fenomenológico inspirado na hidrodinâmica. Os resultados mostram que eventos mais centrais apresentam uma velocidade de expansão maior e uma temperatura menor, condizente com uma fonte que tem um gradiente de pressão maior. Também foi observado que a partícula ? apresenta sempre uma temperatura maior que as outras partículas (p, ?, ?) indicando um desacoplamento anterior dessas partículas em relação às outras. Finalmente, estudamos a utilização do SVT para a reconstrução de V0s, procurando compreender a maneira correta de se utilizar este detector na análise. Os resultados mostram que a utilização desse detector pode levar a uma melhora na eficiência e na pureza durante a reconstrução dessas partículas. / The main goal of this work was to measure the production of the singly strange particles, such as K0, and in Au+Au collisions at ?sNN = 62.4 GeV, inserting these results in a systematic energy scan study. The data were obtained from the STAR detector, one of the RHIC experiments. In addition, we have used the particle production in these collision to study two specific stages of the fireball evolution: the chemical and kinetic freeze-outs. These two stages were studied comparing the ratio between different particles (strange or not) and also the transverse momentum distribution with thermal models fits in order to check possible effects of equilibrated Quark Gluon Plasma (QGP) in the hadron production. The chemical freeze-out was studied comparing the ratios between particles produced in the collision with two different thermal models: one which assumes a equilibrated hadron gas (THERMUS) and another one which assumes a possible non-equilibrated system (SHM). The experimental data were well described by the THERMUS model fit in a great range of energy collisions, mainly at 62.4 GeV. The thermodynamic parameters had been studied as function of the energy in order to verify if it has a smooth or abrupt behavior. The result indicated that this behavior is very smooth with energy. We also compared these results with SHM\'s predictions and, in this comparison, the ratio presented an interesting behavior, suggesting that at low energies the fireball consists of a non-equilibrated system, such as described by SHM model, whereas the model that considers the fireball as a equilibrated hadron gas. The kinetic freeze-out was studied with the transverse momentum spectra using a hydrodynamics inspired model. The results indicate that for the most central events there is a higher expanding velocity and a lower freeze-out temperature. It was also observed that for the particle, the freeze-out temperature is higher than the one for other particles (?, K, p) indicating an earlier decoupling of these particles from the fireball. Finally, we have studied the inclusion for the SVT in the V0 reconstruction analysis, trying to optimize this detector usage in the analysis. The results show that the inclusion of this detector in the analysis can improve the efficiency and purity of the V0 reconstruction in the STAR experiment.
32

Cotidiano experimentado : o processo criativo na prática de ações

Becker, Jéssica Araújo January 2011 (has links)
A presente dissertação desenvolvida na área de poéticas visuais, linha de pesquisa em “contextos e processos de criação, inserção e documentação”, centra-se sobre o processo criativo de ações artísticas realizadas em âmbito urbano e inseridas no contexto cotidiano. Visando a prática de trabalhos próprios, este estudo se desenvolve a partir de ações realizadas no período de 2009-2011, nas cidades de Porto Alegre/ Brasil e Valência/Espanha. Esta produção é aqui analisada recorrendo a referenciais teóricos e práticos do campo da arte, problematizando cada proposição por variados conceitos. / The current dissertation developed in the area of visual poetics, line of research on “contexts and processes of creation, insertion and documentation”, focuses on the creative process of artistic actions undertaken in the urban context and inserted into everyday life. Aiming on practice of own works, this study develops from actions taken during the period of 2009-2011, at the cities of Porto Alegre/Brazil and Valencia/ Spain. This production is also analyzed using theoretical and practical references of the field of art, questioning each proposition on several concepts.
33

A nuvem mesônica e os fatores de forma estranhos do próton / The meson cloud and the strange form factors of the proton

Daniela Morales Tolentino Leite 25 August 2008 (has links)
O objetivo deste trabalho foi incluir o méson escalar $\\kappa$ na núvem de mésons estranhos do próton e verificar se, desta forma, a contribuição de estranheza para as suas propriedades eletromagnéticas poderia ser explicada pelo modelo da núvem mesônica. Os observáveis que quantificam tal contribuição são os fatores de forma estranhos elétrico ($G_E^s$) e magnético ($G_M^s$), que têm sido objeto de grande interesse experimental nos últimos 10 anos. Usando a versão da nuvem que inclui o méson $\\kappa$, nós calculamos $G_E^s$ e $G_M^s$ em função do momento transferido dentro do intervalo 0 $\\leq Q^2 \\leq$ 1,2 GeV$^2$, de modo a abranger toda a gama de dados disponíveis no momento. Comparamos nossos resultados com os dados existentes para $G_E^s$ e $G_M^s$ e encontramos um ótimo acordo entre experimento e modelo, demonstrando que a inclusão do $\\kappa$ na núvem de mésons do próton é fundamental para que o seu conteúdo de estranheza possa ser compreendido. / The goal of this work was to include the scalar $\\kappa$ meson on the meson cloud of the proton, and then to verify if the strangeness contribution to the electromagnetic properties of the proton could be explained by the meson cloud model. The observables that quantify such a contribution are the electric ($G_E^s$) and magnetic ($G_M^s$) strange form factors, which have been subject of great experimental interest in the last 10 years. Using the version of the cloud which includes the $\\kappa$ meson, we calculated $G_E^s$ and $G_M^s$ as a function of the transferred momentum in the interval 0 $\\leq Q^2 \\leq$ 1.2 GeV$^2$, to cover the full range of available data at the time. We compared our results with existing data for $G_E^s$ and $G_M^s$ and we found a good agreement between experiment and model, showing that including $\\kappa$ on the meson cloud of the proton is crucial to understand its strangeness content.
34

Leituras do grotesco em sete narrativas setsuwa de Konjaku Monogatarishû / Reading the grotesque in seven setsuwa tales from Konjaku Monogatarishû

Vinicius Ito Ramos 27 November 2017 (has links)
O presente trabalho propõe uma análise centrada em sete narrativas de cunho secular da seção japonesa contidas na coletânea de narrativas setsuwa denominada Konjaku Monogatarishû do século XIII. As narrativas serão traduzidas para o vernáculo e analisadas pelo viés do corpo grotesco em suas mais diferentes manifestações, assim como explicitado por Bakhtin (2013) e pelo viés do estranhamento tal qual formulado por Wolfgang Kayser (1986). Devido ao fato de as narrativas setsuwa possuírem padrões contrastantes da estética literária e temas vigentes na era Heian, identificou-se a importância do estudo das mesmas pelo viés do grotesco como uma leitura de rompimento com o ideal estético literário, pautando-se pela descrição explícita dos fatos, personagens e ações cotidianas. / The present work aims to analyses seven Japanese secular setsuwa tales included on Konjaku Monogatarishû compilation. The narratives will be translated to nowadays language and analyzed by many points fo view, as studied by grotesque body and others manifestations on Mikhail Bakhtin (2013) theory and by the theory of strangeness by Kayser (1986). Due to the fact that setsuwa tales has different patterns of literary aesthetics and themes in Heian period, the importance of this study by the grotesque as a rupture on literary aesthetics was identified also, because of the approximated description of the facts, figures and the daily actions.
35

Strange dibaryon system produced in the d(π+, K+) reaction at J-PARC / J-PARCにおけるd(π+, K+)反応を用いたストレンジダイバリオン系の研究

Ichikawa, Yudai 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18787号 / 理博第4045号 / 新制||理||1582(附属図書館) / 31738 / 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 永江 知文, 教授 谷森 達, 准教授 成木 恵 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
36

Λ-Λ hyperons: the road to estimate the production cross-section in protonproton collisions

Appagere, Gandharva January 2024 (has links)
In this study, we analyse the $\Lambda$-$\Lambda$ hyperon channel in proton-proton scattering, $pp \mapsto \Lambda\Lambda + K^+K^+, \,\,\Lambda\mapsto p+\pi^-$, with a proton beam energy of $4.5$ GeV using the High Acceptance Di-Electron Spectrometer (HADES) at GSI.The purpose of the study presented here is to measure the production cross-section for the $\Lambda$-$\Lambda$ channel. %at the above beam Kinetic energy. The following measurement will be the first at this energy scale (CoM: $\sqrt{s}=3.46$ GeV).We develop a multi-stage analysis strategy to first determine the acceptance-reconstruction efficiency for the $\Lambda$-$\Lambda$ channel from simulations produced according to phase space.The analysis of data is perforned for three different event selections: inclusive ($ pp \mapsto \Lambda\Lambda + X$), semi-exclusive ($ pp \mapsto \Lambda\Lambda + K^+ +X$) and the fully exclusive.For each selection, the data is represented by a two-dimensional histogram, where the axes correspond to the $p+\pi^-$ invariant mass of the respective $\Lambda$ candidate. %The same strategy was employed on the experimental data to build a $\Lambda$-$\Lambda$ 2D correlation matrix. The \sloppy{$\Lambda$-$\Lambda$ signal} is determined using a Statistical sideband analysis (SSB) and a Linear least squares (LLS) fit.The inclusive selection provides the most significant $\Lambda$-$\Lambda$ signal.Cross-section values corresponding to the two analyses  are calculated as weighted average of the result of the three selections.The production cross-section for $\Lambda$-$\Lambda$ in $pp$ collisions at $\sqrt{s}=3.46$ GeV is measured \sloppy{to be $59\pm27$ nb} (one standard deviation uncertainity).
37

La ballade de Gilbert ; suivi de Le quotidien dans Molloy de Samuel Beckett

Côté-Fournier, Alexandre 09 1900 (has links)
Le roman La ballade de Gilbert raconte l’histoire d’un homme dont la tranquille normalité du quotidien est perturbée lorsqu’il découvre qu’un de ses collègues de longue date fréquente des prostituées. Afin de retrouver son confort, il incite clandestinement ce collègue à se chercher une conjointe, mais cette quête devient peu à peu une profonde obsession qui bouleverse encore plus l’équilibre de sa vie routinière. À travers ce récit s’articule une réflexion sur le quotidien, sur les limites entre l’ordinaire et l’extraordinaire, le familier et l’étrange. L’essai Le quotidien dans Molloy de Samuel Beckett reprend le thème du quotidien afin d’analyser le dialogue entre le familier et l’étrangeté dans ce roman. Molloy présente de nombreux scénarios communs (Eco), qui correspondent très sensiblement d’un point de vue cognitif aux habitudes qui façonnent le quotidien d’un individu. Cet essai explique comment Beckett subvertit ces scénarios pour laisser place à une étrangeté derrière laquelle le familier demeure reconnaissable. / The novel La ballade de Gilbert tells the story of a man whose quiet and ordinary life is troubled when he realises that one of his long time colleagues is seeing prostitutes. To re-establish his comfort, he secretly tries to encourage this colleague to find a mate, but this quest becomes a relentless obsession that overturns even more the order of his life. A reflection about everyday life and the limits between the ordinary and the extraordinary, the familiar and the uncanny, is proposed through this narrative. The essay Le quotidien dans Molloy de Samuel Beckett also touches everyday life by the analysis of the dialogue between familiarity and strangeness. Molloy shows numerous examples of common scenarios (Eco), which correspond very closely, from the cognitive point of view, to the habits that shape an individual’s everyday life. This essay explains how Beckett subverts these scenarios to show a strangeness behind which familiarity remains visible.
38

Étude de la production de méson neutre léger dans la voie de désintégration dimuonique en collision proton-proton à sqrt(s) = 13 TeV en rapidité vers l'avant dans ALICE au LHC du CERN / Study of light-neutral meson production in the dimuon chanel in pp collisions at sqrt(s)=13 TeV at forward rapidity at the CERN LHC with ALICE

Teyssier, Boris 24 November 2017 (has links)
La matière qui nous entoure est formé de hadrons, eux-même constitués de quarks et de gluons. Ces derniers sont des composants élémentaires qui n'existent pas sous forme libre. Cependant nous savons à l'heure actuelle que la matière confinée dans des hadrons peut, dans des conditions de haute température et/ou de haute densité baryonique, se retrouver sous une forme déconfinée de plasma de quarks et de gluons. Pour réaliser expérimentalement les conditions permettant de former ce plasma de quarks et de gluons, nous avons besoin d'une machine capable de faire entrer en collision des noyaux à des énergies très élevées: cela est notamment possible au CERN, où se situe le plus grand accélérateur de particules du monde, le Large Hadron Collider, qui a permis de faire entrer en collisions des noyaux de plomb à une énergie par paire de nucléons de 2.76 et 5.02TeV, et des protons à des énergies allant de 0.9 à 13TeV. Les collisions entre noyaux de plomb permettent, en particulier, d'atteindre les conditions de densité d'énergie nécessaires à la formation de la phase de plasma de quarks et de gluons. Ce travail de thèse contribue à ce programme de physique par l'étude de la production de mésons neutres légers en collisions proton-proton à 13TeV, référence nécessaire pour comprendre les observations en collisions plomb-plomb. L'étude des mésons neutres légers a été menée dans le canal dimuonique par l'analyse du spectre de masse invariante des dimuons de masse inférieure à 1.5 GeV/c², permettant notamment de mesurer les sections efficaces des mésons eta, rho/omega et phi / The ordinary matter surrounding us is made of hadrons which in turn are composed of quarks and gluons. These latter are elementary constituents which cannot be observed in a free state. However it is at present recognized that this matter confined within hadrons can undergo, under extreme conditions of high temperature and/or highnet baryonic density, a transition to a state of deconfined quarks and gluons whichcalled quark gluon plasma. The conditions required to form this quark gluon plasma can be experimentallyachieved using a machine capable of colliding nuclei at very high energies: this is particularly the case at CERN where is located the world’s largest and most powerful particle accelerator, the Large Hadron Collider, which collided Pb ions at a center-of-mass energy of 2.76 to 5.02 TeV per nucleon pair and protons of 0.9 to 13 TeV. Pb-Pb collisionssuch relativistic energies definitely allow for the suitable density conditions to form the quark gluon plasma phase. This thesis work contributes to this physics program by studying the production of neutral light mesons in collisions of proton-proton at 13 TeV, which provides the necessary reference to understand further observations done in Pb-Pb collisions. This study has been performed in the dimuon decay channel by analyzing the dimuon invariant mass spectrum in the region of masses lower than 1.5 GeV/c2 , giving accessthe measurement of the cross sections of eta, rho/omega and phi mesons
39

La ballade de Gilbert ; suivi de Le quotidien dans Molloy de Samuel Beckett

Côté-Fournier, Alexandre 09 1900 (has links)
Le roman La ballade de Gilbert raconte l’histoire d’un homme dont la tranquille normalité du quotidien est perturbée lorsqu’il découvre qu’un de ses collègues de longue date fréquente des prostituées. Afin de retrouver son confort, il incite clandestinement ce collègue à se chercher une conjointe, mais cette quête devient peu à peu une profonde obsession qui bouleverse encore plus l’équilibre de sa vie routinière. À travers ce récit s’articule une réflexion sur le quotidien, sur les limites entre l’ordinaire et l’extraordinaire, le familier et l’étrange. L’essai Le quotidien dans Molloy de Samuel Beckett reprend le thème du quotidien afin d’analyser le dialogue entre le familier et l’étrangeté dans ce roman. Molloy présente de nombreux scénarios communs (Eco), qui correspondent très sensiblement d’un point de vue cognitif aux habitudes qui façonnent le quotidien d’un individu. Cet essai explique comment Beckett subvertit ces scénarios pour laisser place à une étrangeté derrière laquelle le familier demeure reconnaissable. / The novel La ballade de Gilbert tells the story of a man whose quiet and ordinary life is troubled when he realises that one of his long time colleagues is seeing prostitutes. To re-establish his comfort, he secretly tries to encourage this colleague to find a mate, but this quest becomes a relentless obsession that overturns even more the order of his life. A reflection about everyday life and the limits between the ordinary and the extraordinary, the familiar and the uncanny, is proposed through this narrative. The essay Le quotidien dans Molloy de Samuel Beckett also touches everyday life by the analysis of the dialogue between familiarity and strangeness. Molloy shows numerous examples of common scenarios (Eco), which correspond very closely, from the cognitive point of view, to the habits that shape an individual’s everyday life. This essay explains how Beckett subverts these scenarios to show a strangeness behind which familiarity remains visible.
40

Strangeness Photoproduction in the {gamma}p {yields} K{sup 0} {Sigma}{sup +} Reaction

Brian Carnahan January 2003 (has links)
Thesis (Ph.D.); Submitted to the Catholic Univ. of America, Washington, DC (US); 1 May 2003. / Published through the Information Bridge: DOE Scientific and Technical Information. "JLAB-PHY-03-40" "DOE/ER/40150-2764" Brian Carnahan. 05/01/2003. Report is also available in paper and microfiche from NTIS.

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