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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.
11

Elektroslabé procesy v rámci efektivní polní teorie / Elektroslabé procesy v rámci efektivní polní teorie

Soukup, Petr January 2009 (has links)
Title: Electroweak processes in the framework of effective field theory Author: Petr Soukup Department: Institute of Particle and Nuclear Physics Supervisor: RNDr. Karol Kampf, Ph.D. Supervisor's e-mail address: kampf@troja.mff.cuni.cz Abstract: In this thesis, we study electroweak processes within the framework of ef- fective field theory employing the approach of effective Lagrangians. We mainly focus on the decay process H → γγ. A complete set of SU(2) × U(1) invariant dimension- six operators is utilized. We present a brief introduction to GWS Standard model and dimension-six effective operators. One-loop Standard model contribution to the process of H → γγ is then evaluated, followed by calculation of tree-level and one-loop level dimension-six operators contribution to the same process. We then present a brief ge- neral summary of renormalization procedure in quantum field theory. Renormalization of performed calculations is implemented, and possible issues that may arise during renormalization of such non-renormalizable theory are also discussed. In the end, we discuss the obtained results, mainly the dependence of H → γγ decay rate on effective theory's free parameters and the scale of the new physics Λ. Focus is made on possible deviations from Standard model results. The results are plotted in charts....
12

Condições de otimalidade em cálculo das variações no contexto não-suave / Optimality conditions in calculus of variations in the non-smooth context

Signorini, Caroline de Arruda [UNESP] 07 March 2017 (has links)
Submitted by CAROLINE DE ARRUDA SIGNORINI null (carolineasignorini@gmail.com) on 2017-03-22T17:30:47Z No. of bitstreams: 1 Dissertação - versão definitiva [22.03.2017].pdf: 1265324 bytes, checksum: cb95983dd59698aa1bb765a4dd7f9866 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-03-23T13:46:47Z (GMT) No. of bitstreams: 1 signorini_ca_me_sjrp.pdf: 1265324 bytes, checksum: cb95983dd59698aa1bb765a4dd7f9866 (MD5) / Made available in DSpace on 2017-03-23T13:46:47Z (GMT). No. of bitstreams: 1 signorini_ca_me_sjrp.pdf: 1265324 bytes, checksum: cb95983dd59698aa1bb765a4dd7f9866 (MD5) Previous issue date: 2017-03-07 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nosso principal propósito neste trabalho é o estudo de condições necessárias e suficientes de otimalidade para problemas de Cálculo das Variações no contexto não-suave. Este estudo partirá da formulação básica suave, passando por problemas com restrições Lagrangianas, até o caso em que consideramos Lagrangianas não-suaves e soluções absolutamente contínuas. Neste caminho, abordaremos um importante avanço na teoria de Cálculo das Variações: os resultados de existência e regularidade de soluções. Além das condições necessárias, analisaremos as condições suficientes através de um conceito de convexidade generalizada, o qual denominamos E-pseudoinvexidade. / Our main purpose in this work is the study of necessary and sufficient optimality conditions for Calculus of Variations problems in the nonsmooth context. This study will comprehend the smooth basic formulation, constrained problems (with Lagrangian restrictions), non-smooth Lagrangians and absolutely continuous solutions. Moreover, we will approach an important advance in Calculus of Variations theory: the existence and regularity of solutions. In addition to necessary conditions, we will analyze sufficient conditions through a generalized convexity concept, which we called E-pseudoinvexity. / FAPESP: 2014/24271-6
13

Field Theoretic Lagrangian From Off-shell Supermultiplet Gauge Quotients

Katona, Gregory 01 January 2013 (has links)
Recent efforts to classify off-shell representations of supersymmetry without a central charge have focused upon directed, supermultiplet graphs of hypercubic topology known as Adinkras. These encodings of Super Poincare algebras, depict every generator of a chosen supersymmetry as a node-pair transformtion between fermionic bosonic component fields. This research thesis is a culmination of investigating novel diagrammatic sums of gauge-quotients by supersymmetric images of other Adinkras, and the correlated building of field theoretic worldline Lagrangians to accommodate both classical and quantum venues. We find Ref [40], that such gauge quotients do not yield other stand alone or "proper" Adinkras as afore sighted, nor can they be decomposed into supermultiplet sums, but are rather a connected "Adinkraic network". Their iteration, analogous to Weyl's construction for producing all finite-dimensional unitary representations in Lie algebras, sets off chains of algebraic paradigms in discrete-graph and continuous-field variables, the links of which feature distinct, supersymmetric Lagrangian templates. Collectively, these Adiankraic series air new symbolic genera for equation to phase moments in Feynman path integrals. Guided in this light, we proceed by constructing Lagrangians actions for the N = 3 supermultiplet YI /(iDI X) for I = 1, 2, 3, where YI and X are standard, Salam-Strathdee superfields: YI fermionic and X bosonic. The system, bilinear in the component fields exhibits a total of thirteen free parameters, seven of which specify Zeeman-like coupling to external background (magnetic) fluxes. All but special subsets of this parameter space describe aperiodic oscillatory responses, some of which are found to be surprisingly controlled by the golden ratio, [phi] = 1.61803, Ref [52]. It is further determined that these Lagrangians allow an N = 3 - > 4 supersymmetric extension to the Chiral-Chiral and Chiral-twistedChiral multiplet, while a subset admits two inequivalent such extensions. In a natural proiii gression, a continuum of observably and usefully inequivalent, finite-dimensional off-shell representations of worldline N = 4 extended supersymmetry are explored, that are variate from one another but in the value of a tuning parameter, Ref [53]. Their dynamics turns out to be nontrivial already when restricting to just bilinear Lagrangians. In particular, we find a 34-parameter family of bilinear Lagrangians that couple two differently tuned supermultiplets to each other and to external magnetic fluxes, where the explicit parameter dependence is unremovable by any field redefinition and is therefore observable. This offers the evaluation of X-phase sensitive, off-shell path integrals with promising correlations to group product decompositions and to deriving source emergences of higher-order background flux-forms on 2-dimensional manifolds, the stacks of which comprise space-time volumes. Application to nonlinear sigma models would naturally follow, having potential use in M- and F- string theories.

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