The classical field theory of Schwinger pair creation can be described using an effective Schrodinger equation with an inverted harmonic oscillator Hamiltonian. It is a well known fact that the inverted harmonic oscillator admits a canonical transformation to a Q.P type Berry-Keating Hamiltonian. In this thesis we demonstrate that the classical field theory of Schwinger pair creation has a hidden scale invariance described by the quantum mechanics of an attractive inverse square potential in the canonically rotated (Q,P) coordinates of the inverted harmonic oscillator. The quantum mechanics of the inverse square potential is well known because of the problem of fall to the center and the associated ambiguities in the boundary condition. It is also well known as a description of the physics of pair creation in the presence of an event horizon and black hole decay. We use point particle effective field theory (PPEFT) to derive the boundary condition which describes pair creation. This leads to the addition of an inevitable Dirac delta function with imaginary coupling to the inverse square potential, describing the physics of the source. This non-hermitian physics leads to the Klein paradox. The conservation loss is due to the charged pairs being produced during tunneling. / Thesis / Master of Science (MSc)

Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. On t.p. xi is represented by the Greek letter. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:25:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-24Bitstream added on 2014-06-13T19:32:37Z : No. of bitstreams: 1 cardoso_tr_me_guara.pdf: 1016979 bytes, checksum: e22b97fead10209e15852a61078f65bf (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O formalismo de primeira ordem de Du n-Kemmer-Petiau (DKP) descreve partículas de spin 0 e spin 1 e tem sido utilizado na análise de interações relativísticas de hádrons com núcleos como uma alternativa para análise baseada nos formalismos de segunda ordem convencionais de Klein-Gordon e Proca. Apresentamos a equação geral de DKP, discutimos as condições sobre as interações que levam a uma corrente conservada e os efeitos das transformações de paridade, conjugação de carga e reversão temporal. Adotando uma representação especí ca para as matrizes de DKP, estabelecemos as equações de movimento para os componentes do espinor de DKP na presença das interações escalares e vetoriais. Salientamos que o componente espacial do potencial vetorial não-mínimo não pode ser absorvido no espinor. Mostramos que o componente espacial do potencial vetorial não-mínimo poderia ser irrelevante para a formação de estados ligados para potenciais que se anulam no in nito mas que a sua presença é uma condição sine qua non para o con namento. Algumas aplicações em potenciais unidimensionais são usadas para mostrar que o paradoxo de Klein nunca aparece no caso do acoplamento vetorial não-mínimo, contrário ao que ocorre para um potencial vetorial minimamente acoplado. Um aparente paradoxo relacionado à localização de bósons na presença de potenciais fortes é resolvido através da introdução dos conceitos de massa efetiva e comprimento de onda Compton efetivo / The rst-order Du n-Kemmer-Petiau (DKP) formalism describes spin-0 and spin-1 particles and has been used to analyze relativistic interactions of hadrons with nuclei as an alternative to their conventional second-order Klein-Gordon and Proca counterparts. We present the general DKP equation, discuss conditions on the interactions which lead to a conserved current and e ects of parity, charge-conjugation and time-reversal transformations. Adopting a speci c representation for the DKP matrices, we set up the equations for the components of the DKP spinor in the presence of scalar and vector interactions. We point out that the space component of the nonminimal vector potential can not be absorbed into the spinor. We show that the space component of the nonminimal vector potential could be irrelevant for the formation of bound states for potentials vanishing at in nity but its presence is a sine qua non condition for con nement. Some aplications in unidimensional potentials are used to show that Klein's paradox never appears in the case of a nonminimal vector potential, contrary to what occurs for a minimally coupled vector potential. An apparent paradox related to the localization of bosons in the presence of strong potentials is solved by introducing the concepts of e ective mass and e ective Compton wavelength

Thesis. 1976. Ph.D. cn--Massachusetts Institute of Technology. Dept of Physics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. Vita. / Includes bibliographical references. / Ph.D.cn

This dissertation dicusses two topics; the cross section measurement of ϓ(1S) meson pair production [1] and simulation studies of High Granularity Calorimetry (HGCal). The first part of the dissertation is dedicated for the analysis of ϓ(1S) meson pair production and measurement of its cross section. The data for this analysis were collected by the CMS experiment at Large Hadron Collider (LHC) at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 20.7 fb −1 . Simultaneous production of two ϓ(1S) mesons is observed for the first time with 38 events, corresponding to a local significance exceeding five standard deviations from the expected combinatorial background b-quark decays. Both ϓ(1S) candidates are fully reconstructed via their decays to μ + μ − . The fiducial acceptance of the detector is measured from the simulation and is defined by an absolute Υ(1S) rapidity smaller than 2.0. To minimize the model-dependence, the acceptance and efficiency corrections are calculated on an event-by-event basis using measured ϓ meson and muon momenta. The fiducial cross section of ϓ(1S) meson production, assuming both ϓ(1S) mesons decay isotropically, is measured to be 68.8 ± 12.7 (stat) ± 7.4 (syst) ± 2.8 (B) pb, where the third uncertainty comes from the uncertainty in the branching fraction of ϓ(1S) decays to μ + μ − . Different assumptions about ϓ productions imply modifications to the cross section ranging from −38% to +36%. Cross section measurement of ϓ pair production will provide better understanding of the parton vstructure of proton and enhance precision of existing particle production models. LHC is planning to increase luminosity and energy of colliding protons. Due to accumulated radiation damage and to improve detector performance CMS experiment is expected to undergo upgrade plans. Hadron calorimeter is among them, and it is planned to be replaced with better performance high granularity calorimetry (HGCal). HGCal needs to be integrated with existing components of CMS and its smooth functioning is essential. The second part of the dissertation describes simulation studies performed to validate readiness of HGCal for the Phase II upgrade.

Orientador: Antonio Soares de Castro / Banca: Julio Marny Hoff da Silva / Banca: Bruto Max Pimentel Escobar / Resumo: O formalismo de primeira ordem de Du n-Kemmer-Petiau (DKP) descreve partículas de spin 0 e spin 1 e tem sido utilizado na análise de interações relativísticas de hádrons com núcleos como uma alternativa para análise baseada nos formalismos de segunda ordem convencionais de Klein-Gordon e Proca. Apresentamos a equação geral de DKP, discutimos as condições sobre as interações que levam a uma corrente conservada e os efeitos das transformações de paridade, conjugação de carga e reversão temporal. Adotando uma representação especí ca para as matrizes de DKP, estabelecemos as equações de movimento para os componentes do espinor de DKP na presença das interações escalares e vetoriais. Salientamos que o componente espacial do potencial vetorial não-mínimo não pode ser absorvido no espinor. Mostramos que o componente espacial do potencial vetorial não-mínimo poderia ser irrelevante para a formação de estados ligados para potenciais que se anulam no in nito mas que a sua presença é uma condição sine qua non para o con namento. Algumas aplicações em potenciais unidimensionais são usadas para mostrar que o paradoxo de Klein nunca aparece no caso do acoplamento vetorial não-mínimo, contrário ao que ocorre para um potencial vetorial minimamente acoplado. Um aparente paradoxo relacionado à localização de bósons na presença de potenciais fortes é resolvido através da introdução dos conceitos de massa efetiva e comprimento de onda Compton efetivo / Abstract: The rst-order Du n-Kemmer-Petiau (DKP) formalism describes spin-0 and spin-1 particles and has been used to analyze relativistic interactions of hadrons with nuclei as an alternative to their conventional second-order Klein-Gordon and Proca counterparts. We present the general DKP equation, discuss conditions on the interactions which lead to a conserved current and e ects of parity, charge-conjugation and time-reversal transformations. Adopting a speci c representation for the DKP matrices, we set up the equations for the components of the DKP spinor in the presence of scalar and vector interactions. We point out that the space component of the nonminimal vector potential can not be absorbed into the spinor. We show that the space component of the nonminimal vector potential could be irrelevant for the formation of bound states for potentials vanishing at in nity but its presence is a sine qua non condition for con nement. Some aplications in unidimensional potentials are used to show that Klein's paradox never appears in the case of a nonminimal vector potential, contrary to what occurs for a minimally coupled vector potential. An apparent paradox related to the localization of bosons in the presence of strong potentials is solved by introducing the concepts of e ective mass and e ective Compton wavelength / Mestre

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<p>This thesis presents two measurements of the top quark pair production cross section at sqrt{s} = 1.96 TeV using data from the DØ experiment. Both measurements are performed in the dilepton final state and make use of secondary vertex b-tagging. With 158 pb^-1 of data in the electron-muon final state, the measured cross section is:</p><p>σ(top-antitop) = 11.1 +5.8 -4.3 (stat) +- 1.4 (syst) +- 0.7 (lumi) pb.</p><p>With 425 pb^-1 of data in the electron+track and muon+track final states, the measured cross section is:</p><p>sigma(top-antitop) = 6.3 +2.1 -1.8 (stat) +- 1.1 (syst) +- 0.4 (lumi) pb.</p><p>Both measurements are in agreement with the prediction from perturbative QCD calculations. In addition, an estimate of the DØ silicon detector lifetime is presented. The radiation damage is determined by studying the depletion voltage of the silicon sensors as a function of time. Based on this data the silicon detector is estimated to remain operational up to delivered luminosities of 6-8 fb^-1.</p>

This thesis presents two measurements of the top quark pair production cross section at sqrt{s} = 1.96 TeV using data from the DØ experiment. Both measurements are performed in the dilepton final state and make use of secondary vertex b-tagging. With 158 pb-1 of data in the electron-muon final state, the measured cross section is: σ(top-antitop) = 11.1 +5.8 -4.3 (stat) +- 1.4 (syst) +- 0.7 (lumi) pb. With 425 pb-1 of data in the electron+track and muon+track final states, the measured cross section is: sigma(top-antitop) = 6.3 +2.1 -1.8 (stat) +- 1.1 (syst) +- 0.4 (lumi) pb. Both measurements are in agreement with the prediction from perturbative QCD calculations. In addition, an estimate of the DØ silicon detector lifetime is presented. The radiation damage is determined by studying the depletion voltage of the silicon sensors as a function of time. Based on this data the silicon detector is estimated to remain operational up to delivered luminosities of 6-8 fb-1.