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A search for supersymmetry with the ATLAS detector using kinematic shape constraints in events containing one electron or muonShort, Daniel R. January 2012 (has links)
The ATLAS experiment is used to observe the √s=7 TeV proton-proton collisions produced by the LHC at CERN. This gives an unprecedented opportunity to search for physics beyond the Standard Model at hitherto unexplored kinematic regimes. Supersymmetry (SUSY) provides interesting solutions to a variety of theoretical problems that may be encountered in the Standard Model at high energy scales, while providing signatures that may be observed at the LHC. However, in order to produce a search that is sensitive to SUSY it is vital to understand how the physics that has been discovered to date may produce signatures that mimic those expected from SUSY. Statistical models are constructed using both Monte Carlo and data-driven predictions of various background processes. The expectations are compared to the observed data for selections containing one electron or muon, each in association with jets and missing transverse momentum. Kinematic variable shapes, in the form of histograms, are used to enhance the sensitivity of the search. Squark and gluino masses in a MSUGRA SUSY model are excluded up to 1200 GeV, while gluino masses up to 900 GeV are excluded in a simplified SUSY model. Model-independent limits are also set, excluding theoretical models with efficiency times cross section above 1 fb.
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Measurement of CP violation in B→DK* decays with the LHCb experimentSmith, Edmund Robert Henry January 2014 (has links)
This thesis reports an analysis of 3.0fb<sup>-1</sup> of pp collision data collected by the LHCb experiment in 2011 and 2012. Decays of neutral B mesons to neutral D mesons and excited neutral kaons are reconstructed, because of their sensitivity to the CP-violating phase of the CKM matrix, γ.
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Determinação da razão de ramificação e dos fatores de forma do decaimento semi-leptônico \"K IND.L\"-> \"\"pi\" POT.0\" \"\"pi\" POT.+/-\" e \"ANTPOT.-/+ \"nü\"\". / Determination of the branching ratio and form factors of semi-leptonic decay \"K IND.L\"-> \"\"pi\" POT.0\" \"\"pi\" POT.+/-\" e \"ANTPOT.-/+ \"nü\"\".Santos, Edivaldo Moura 24 August 2005 (has links)
Mediu-se a razão de ramificação do decaimento semi-leptônico \"K IND.L->\"pi\"POT.0\"\"pi\" POT, +/-\" e \"ANTPOT.-/+nu\" (\"BR IND.\"K POT.0\"IND.E4\" = [5.19 =/- \"0.09 IND.sist\"] X \"10 POT.-5\"), baseado numa amostra de 4000 eventos sobre um fundo residual a ser subtraído de 143 (3.6%) eventos. Os dados foram coletados pelo experimento KTeV no Fermilab. A contaminação residual é compatível com \"K IND.->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\"\"gama\" ou \"K IND.L->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\" ou \"K IND.L\" ->\"pi\" POT.=/-\" e \" ANTPOT.=/-\"nu\" na presença de um ou dois fótons acidentais, respectivamente. A contribuição dominante ao erro sistemático advém de uma discrepância observada entre dados/Monte Carlo com respeito à eficiência de detecção ao longo da direção do feixe de káons. O modo de normalização utilizado na medida da razão de ramificação foi \"K IND.L\" ->\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\". Correções radiativas eletromagnéticas de ordem \"\"alfa\"IND.QED\" foram incluídas no Monte Carlo de simulação, tendo a fração radiativa sido conferida por meio de um cálculo analítico, incluindo bremsstrahlung interno e correções virtuais, das quais a correção de vértice fornece uma contribuição finita após o processo de renormalização. Por meio de um ajuste ao espectro e construído do decaimento, três dos fatores de forma que parametrizam o elemento de matriz hadrônica também foram medidos, cujos valores indicam uma violação da regra empírica \"delta\"I=1/2 de cerca de 2%. A dependência, em primeira ordem, de um dos fatores de forma com o momento transferido aos léptons \"q POT.2\" também foi obtida, possibilitando a resolução da ambiguidade quadrática entre \"\"gama\"IND.K\" IND.E.4\" a constante de acoplamento \"L IND.3\" em Teoria de Perturbação Quiral e permitindo uma medida direta dessa constante (\"L IND.3\"=[-4.0 =/- 0.3] X \"10 POT.-3\"). / We have measured the branching fraction of the \"K IND.L->\"pi\"POT.0\"\"pi\" POT, +/-\" e \"ANTPOT.-/+nu\" decay (\"BR IND.\"K POT.0\"IND.E4\" = [5.19 =/- \"0.09 IND.sist\"] X \"10 POT.-5\"), based on a 4000 candidates sample over a residual background of 143 (3.6%) events. The data was collected by the KTeV experiment at Fermilab. The remaining contamination is consistent with \"K IND.->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\"\"gama\" ou \"K IND.L->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\" ou \"K IND.L\" ->\"pi\" POT.=/-\" e \" ANTPOT.=/-\"nu\" plus one or two accidental photons, respectively. The leading contribution to the systematic error comes from an observed discrepancy between data/Monte Carlo for the detection efficiency along the kaon beam direction. The \"K IND.L\" ->\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\" decay was used as normalization mode for the purpose of branching fraction measurement. Radiative corrections of order \"\"alfa\"IND.QED\" were included into the Monte Carlo, the radiative fraction being crosschecked through an analytical calculation, which included internal bremsstrahlung and virtual corrections, of which the vertex correction gives a finite contribution after renormalization. Through a fit to the reconstructed decay spectrum, three form factors appearing in the parametrization of the hadronic matrix element were measured, whose values allow for a violation of the empirical \"delta\"I=1/2 rule of about 2%. We have also measured the first order dependence on the transfered momentum to the leptons of one of the form factors, solving the quadratic ambiguity between \"\"gama\"IND.K\" IND.E.4\" and the low energy coupling constant \"L IND.3\" from Chiral Perturbation Theory, allowing for a direct measurement of this constant (\"L IND.3\"=[-4.0 =/- 0.3] X \"10 POT.-3\").
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Queer bodies and settlements : the pertinence of queer theory in the fields of queer history and trans politics, disability and 'curative education', quantum physics and experimental art : an interdisciplinary and transnational account of three socio-cultural and filmic research projectsGarel, Stefan Jack January 2008 (has links)
What is queer? What is queer? What is queer theory? Where can it go from here? This thesis sets out to explore the origins and influences of queer theory before investigating the present and the future spaces (ie, bodies and settlements) it can potentially move into. Three distinct experiments of fieldwork and ethnographic filmmaking test the truths and potentialities of queer theory when relating to queer bodies and settlements. That is to say that each chapter balances a film and its supporting text by embracing the value and urgency of practice led research. The first chapter questions queer history and details the importance of emerging trans politics in the post-gender, leftist, avant-garde, queer activist and militant space of Bologna. Queer bodies, case one: transgender and transsexual perspectives. Settlements, case one: Bologna and Lido di Classe (Italy). The second chapter considers the interface between disability theory and queer theory with particular attention paid to the practical theory of ‘curative education’. Defined by Rudolf Steiner in 1922 and further developed by Karl König with the foundation of the Camphill movement in 1944, curative education privileges the social model over the medical model in the field of disability so that disability is in fact ability. Queer bodies, case two: learning differences and disabilities perspectives. Settlements, case two: Berlin (Germany), Chatou and La Rochelle (France), Barry and Glasallt Fawr (Wales, United Kingdom). The third chapter uses queer perspectives to promote the relevance of quantum physics to the human body, thus involving contemporary dance, physical theatre and the arts more generally to address and redress the chiasm between science and technology on the one hand, and arts, humanities and socio-cultural sciences on the other. Queer bodies, case three: the inescapably queer reality of the physical world. Settlements, case three: multiple locations in Tuscany (Italy), and Thamesmead, London (England, United Kingdom). This thesis brings notions of queer and otherness deceptively close to notions of the self. Otherness and queerness become mirrors in which our own queerness comes into view.
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Determinação da razão de ramificação e dos fatores de forma do decaimento semi-leptônico \"K IND.L\"-> \"\"pi\" POT.0\" \"\"pi\" POT.+/-\" e \"ANTPOT.-/+ \"nü\"\". / Determination of the branching ratio and form factors of semi-leptonic decay \"K IND.L\"-> \"\"pi\" POT.0\" \"\"pi\" POT.+/-\" e \"ANTPOT.-/+ \"nü\"\".Edivaldo Moura Santos 24 August 2005 (has links)
Mediu-se a razão de ramificação do decaimento semi-leptônico \"K IND.L->\"pi\"POT.0\"\"pi\" POT, +/-\" e \"ANTPOT.-/+nu\" (\"BR IND.\"K POT.0\"IND.E4\" = [5.19 =/- \"0.09 IND.sist\"] X \"10 POT.-5\"), baseado numa amostra de 4000 eventos sobre um fundo residual a ser subtraído de 143 (3.6%) eventos. Os dados foram coletados pelo experimento KTeV no Fermilab. A contaminação residual é compatível com \"K IND.->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\"\"gama\" ou \"K IND.L->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\" ou \"K IND.L\" ->\"pi\" POT.=/-\" e \" ANTPOT.=/-\"nu\" na presença de um ou dois fótons acidentais, respectivamente. A contribuição dominante ao erro sistemático advém de uma discrepância observada entre dados/Monte Carlo com respeito à eficiência de detecção ao longo da direção do feixe de káons. O modo de normalização utilizado na medida da razão de ramificação foi \"K IND.L\" ->\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\". Correções radiativas eletromagnéticas de ordem \"\"alfa\"IND.QED\" foram incluídas no Monte Carlo de simulação, tendo a fração radiativa sido conferida por meio de um cálculo analítico, incluindo bremsstrahlung interno e correções virtuais, das quais a correção de vértice fornece uma contribuição finita após o processo de renormalização. Por meio de um ajuste ao espectro e construído do decaimento, três dos fatores de forma que parametrizam o elemento de matriz hadrônica também foram medidos, cujos valores indicam uma violação da regra empírica \"delta\"I=1/2 de cerca de 2%. A dependência, em primeira ordem, de um dos fatores de forma com o momento transferido aos léptons \"q POT.2\" também foi obtida, possibilitando a resolução da ambiguidade quadrática entre \"\"gama\"IND.K\" IND.E.4\" a constante de acoplamento \"L IND.3\" em Teoria de Perturbação Quiral e permitindo uma medida direta dessa constante (\"L IND.3\"=[-4.0 =/- 0.3] X \"10 POT.-3\"). / We have measured the branching fraction of the \"K IND.L->\"pi\"POT.0\"\"pi\" POT, +/-\" e \"ANTPOT.-/+nu\" decay (\"BR IND.\"K POT.0\"IND.E4\" = [5.19 =/- \"0.09 IND.sist\"] X \"10 POT.-5\"), based on a 4000 candidates sample over a residual background of 143 (3.6%) events. The data was collected by the KTeV experiment at Fermilab. The remaining contamination is consistent with \"K IND.->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\"\"gama\" ou \"K IND.L->\"\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\" ou \"K IND.L\" ->\"pi\" POT.=/-\" e \" ANTPOT.=/-\"nu\" plus one or two accidental photons, respectively. The leading contribution to the systematic error comes from an observed discrepancy between data/Monte Carlo for the detection efficiency along the kaon beam direction. The \"K IND.L\" ->\"pi\"POT.=/-\" e \" ANTPOT.=/-\"nu\" decay was used as normalization mode for the purpose of branching fraction measurement. Radiative corrections of order \"\"alfa\"IND.QED\" were included into the Monte Carlo, the radiative fraction being crosschecked through an analytical calculation, which included internal bremsstrahlung and virtual corrections, of which the vertex correction gives a finite contribution after renormalization. Through a fit to the reconstructed decay spectrum, three form factors appearing in the parametrization of the hadronic matrix element were measured, whose values allow for a violation of the empirical \"delta\"I=1/2 rule of about 2%. We have also measured the first order dependence on the transfered momentum to the leptons of one of the form factors, solving the quadratic ambiguity between \"\"gama\"IND.K\" IND.E.4\" and the low energy coupling constant \"L IND.3\" from Chiral Perturbation Theory, allowing for a direct measurement of this constant (\"L IND.3\"=[-4.0 =/- 0.3] X \"10 POT.-3\").
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Negative frequency at the horizon : scattering of light at a refractive index frontJacquet, Maxime J. January 2017 (has links)
This thesis considers the problem of calculating and observing the mixing of modes of positive and negative frequency in inhomogeneous, dispersive media. Scattering of vacuum modes of the electromagnetic field at a moving interface in the refractive index of a dielectric medium is discussed. Kinematics arguments are used to demonstrate that this interface may, in a regime of linear dispersion, act as the analogue of the event horizon of a black hole to modes of the field. Furthermore, a study of the dispersion of the dielectric shows that five distinct configurations of modes of the inhomogeneous medium at the interface exist as a function of frequency. Thus it is shown that the interface is simultaneously a black- and white-hole horizon-like and horizonless emitter. The role, and importance, of negative-frequency modes of the field in mode conversion at the horizon is established and yields a calculation of the spontaneous photonic flux at the interface. An algorithm to calculate the scattering of vacuum modes at the interface is introduced. Spectra of the photonic flux in the moving and laboratory frame, for all modes and all realisable increase in the refractive index at the interface are computed. As a result of the various mode configurations, the spectra are highly structured in intervals with black-hole, white-hole and no horizon. The spectra are dominated by a negative-frequency mode, which is the partner in any Hawking-type emission. An experiment in which an incoming positive-frequency wave is populated with photons is assembled to observe the transfer of energy to outgoing waves of positive and negative frequency at the horizon. The effect of mode conversion at the interface is clearly shown to be a feature of horizon physics. This is a classical version of the quantum experiment that aims at validating the mechanism of Hawking radiation.
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