Made available in DSpace on 2015-09-17T15:26:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-12. Added 1 bitstream(s) on 2015-09-17T15:45:48Z : No. of bitstreams: 1 000848245.pdf: 624236 bytes, checksum: c69b524f4c9580903dec4bfab14e6987 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nestatese, uma dada amplitude de espalhamento de supercordas envolvendo um operador de vértice da corda fechada e N operadores de vértice da corda aberta em AdS5 ×S5 é detalhadamente estudada, utilizando-se o formalismo de espinores puros. Após rever o material de apoio e realizar alguns cálculos preliminares, mostramos que a amplitude nível-de-árvore contendo um estado de supergravidade e N estados de super-Yang-Mills localizados em uma D3-brana próxima à fronteira de AdS5 pode ser expressa como uma integral no superespaço harmônico N = 4, d = 4 em termos dos supercampos de supergravidade e super-Yang-Mills, demonstrando assim uma conjectura feita recentemente / In this thesis, a particular superstring scattering amplitude involving one closed string and N open string vertex operators in AdS5 ×S5 is studied in detail, usingthe pure-spinor formalism. After reviewing some background material and performing a few preliminary calculations, we show that the tree-level amplitude containing one supergravity state and N super-Yang-Mills states located on a D3-brane near the AdS5 boundary can be expressed as an N = 4, d = 4 harmonic superspace integral in terms of the supergravity and super-Yang-Mills superfields, thus proving a conjecture recently made / FAPESP: 2010/19596-2

Made available in DSpace on 2014-06-11T19:32:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-10Bitstream added on 2014-06-13T19:21:26Z : No. of bitstreams: 1 zuniga_hg_dr_ift.pdf: 1022667 bytes, checksum: 4bb9cc5ce799137c7e017ee6d1a8f284 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Primeiro vamos dar uma breve revisão sobre o artigo de Nekrasov “ Lectures on curved beta-gamma systems, pure spinors, and anomalies”, a fim de mostrar que o formalismo de espinor puro é livre de anomalia quando a origem é removido do espaço espinor puro. Desta forma, damos uma nova proposta para os operadores de imagem no formalismo de espinor puro mínimo. Nós calculamos amplitudes de espalhamento a nível de árvore, realizando a integração no espaço espinor puro como uma integral de Cauchy tipo multidimensional. A amplitude é escrita em termos de variáveis do espaço de espinor puro projetivo, o que é muito útil na hora de relacionar rigorosamente as versões mínima e não mínima do formalismo de espinor puro. A linguagem natural para relacionar esses formalismos é o isomorfismo de Cech-Dolbeault. Além disso, o cociclo de Dolbeault correspondente à amplitude de espalhamento a nível de árvore deve ser avaliada no espaço compacto SO(10)/SU(5) em vez de tudo o espaço de espinor puro, o que significa que a origem é removido neste espaço. Nós também obtimos uma relação entre a função de Green para um campo escalar sem massa em dez dimensões e as amplitude de espalhamento a nível de árvore. Os fatores globais constantes nas amplitudes de espalhamento são muito importante, porque eles precisam satisfazer as condições de unitariedade e S-dualidade [66]. Estes coeficientes não tinham sido computados no formalismo espinor puro, devido à dificuldade para resolver as integrais no espaço de espinores puro. Nós calculamos estas integrais usando o formalismo de espinor puro não mínimo. Assim, encontramos os coeficientes das amplitudes de um e dois-“loop” para quatro pontos sem massa. Contrastando com as dificuldades matemáticas no formalismo RNS, em que o desconhecimento das normalizações... / First, we give a brief review about the Nekrasov’s paper “Lectures on curved betagamma systems, pure spinors, and anomalies” in order to show the pure spinor formalism is anomaly free when the origin is removed from the pure spinor space. In this way we give a new proposal for the “picture lowering” operators in the minimal pure spinor formalism. We compute the tree level scattering amplitude by performing the integration over the pure spinor space as a multidimensional Cauchy-type integral. The amplitude is written in terms of the projective pure spinor variables, which turns out to be useful to relate rigorously the minimal and non-minimal versions of the pure spinor formalism. The natural language for relating these formalisms is the Cech-Dolbeault isomorphism. Moreover, the Dolbeault cocycle corresponding to the three-level scattering amplitude must be evaluated in SO(10)/SU(5) instead of the whole pure spinor space, which means that the origin is removed from this space. We also relate the Green’s function for the massless scalar field in ten dimensions to the tree-level scattering amplitude and comment about the scattering amplitude at higher orders. The overall constan factors in the scattering amplitudes are very important because they need to satisfy the unitarity and S-duality conditions [66]. These coefficients have not been computed in the pure spinor formalism due to the difficulty to solve the integrals on the pure spinors space. We compute these integrals by using the non-minimal pure spinor formalism. So, we find the coefficients of the massless one and two-loop four-point amplitude from first principles. Contrasting with the mathematical difficulties in the RNS formalism where unknown normalizations of chiral determinant formulæ force the two-loop coefficient to be... (Complete abstract click electronic access below)

Orientador: Abraham Hirsz Zimerman / Banca: Paulo Teotônio Sobrinho / Banca: José Francisco Gomes / Resumo: Neste trabalho estudamos a hierarquia de modelos integráveis de AKNS supersimétrico. Abordamos também um modelo da mesma hierarquia, correspondendo a um sistema relativístico. Este modelo foi desenvolvido a partir da mesma estrutura algébrica e portanto corresponde ao modelo de Lund-Regge supersimétrico. Incluímos estudos de outros aspectos refentes a transformações de simetria e supersimetria de forma sistemática para o modelo de AKNS supersimétrico não relativístico. Obtemos as soluções tipo sóliton dos modelos integráveis (em 2 dimensões) sob consideração / Abstract: In this work we study the supersymmetric AKNS integrable model hierarchy. We discuss also a relativistic model of the same hierarchy. This model was developed from the same algebraic structure and therefore corresponds to the supersymmetric Lund-Regge model. We include a systematic study on other aspects of the symmetries and supersymmetries transformations of the non relativistic supersymmetric AKNS. We obtain soliton Solutions of the integrable models (in two dimensions) under consideration / Mestre

Future Higgs factories can reach impressive precision on Higgs property measurements. In this paper, instead of conventional focus of Higgs precision in certain interaction bases, we explore its sensitivity to new physics models at the electron-positron colliders. In particular, we study two categories of new physics models, Standard Model (SM) with a real scalar singlet extension, and Two Higgs Double Model (2HDM) as examples of weakly-interacting models, Minimal Composite Higgs Model (MCHM) and three typical patterns of the more general operator counting for strong interacting models as examples of strong dynamics. We perform a global fit to various Higgs search channels to obtain the 95% C.L. constraints on the model parameter space. In the SM with a singlet extension, we obtain the limits on the singlet-doublet mixing angle sin theta, as well as the more general Wilson coefficients of the induced higher dimensional operators. In the 2HDM, we analyze tree level effects in tan beta vs. cos(beta-alpha) plane, as well as the one-loop contributions from the heavy Higgs bosons in the alignment limit to obtain the constraints on heavy Higgs masses for different types of 2HDM. In strong dynamics models, we obtain lower limits on the strong dynamics scale. In addition, once deviations of Higgs couplings are observed, they can be used to distinguish different models. We also compare the sensitivity of various future Higgs factories, namely Circular Electron Positron Collider (CEPC), Future Circular Collider (FCC)-ee and International Linear Collider (ILC).

For several theoretically and experimentally motivated reasons, super- symmetry (SUSY) has for some time been identified as an interesting candidate for a theory of fundamental particle physics beyond the Stan- dard Model. The ATLAS collaboration, of which I am a member, possess a detector emplaced in the Large Hadron Collider experiment at CERN. If SUSY does in fact describe our universe, then it is hoped that evidence of it will be visible in data collected in the ATLAS detector. I present an analysis looking for a particular signature that could indicate the presence of SUSY; events containing two like-charge leptons (e or μ). This signature benefits from having both low Standard Model backgrounds as well as potential to observe several SUSY scenarios, par- ticularly those involving strong production processes. These include pair production of squarks and gluinos. The latter of these are particularly relevant for the analysis presented herein since gluinos are Majorana fermions; hence they can decay to produce like-charge leptons. The analysis considers several SUSY production topologies determined from a variety of simplified and phenomenological models. One of the core pieces of any ATLAS analysis is estimating the expected backgrounds in the signal regions. These backgrounds arise both from known Standard Model production processes that can produce the same final state as the SUSY models being targeted, as well as detector mismeasurement effects. One important background in the like-charge analysis is that of “fake” leptons; these are jets that have been misclassified as either electrons or muons by the reconstruction algorithms. A large portion of this thesis is dedicated to introducing novel techniques for robustly estimating these backgrounds, and evaluating their relative performance.

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京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22626号 / 理博第4615号 / 新制||理||1663(附属図書館) / 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 中家 剛, 准教授 WENDELL Roger, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

This thesis presents a search for Supersymmetry in final states containing two same-flavor opposite-sign leptons, jets and large missing transverse momentum. The search makes use of 36.1 fb−1 of proton-proton collision data collected at a center-of-mass energy of √s = 13 TeV by the ATLAS detector at the Large Hadron Collider. Two signal scenarios, which both involve the pair-production of squarks or gluinos decaying into final states with two leptons and the lightest supersymmetric particle, are targeted by the analysis. The first scenario considers decay chains with a leptonically decaying Z boson and is characterized by a peak in the dilepton invariant mass distribution. In the second scenario, decays through intermediate sleptons or an off-shell Z boson are considered. Such processes lead to a kinematic endpoint in the dilepton invariant mass distribution. The main Standard Model backgrounds include the pair-production of top quarks and direct production of Z bosons. These backgrounds are estimated with two data-driven methods. The observed data is found to be consistent with the Standard Model expectation and the results are interpreted in simplified Supersymmetry models for gluino and squark pair-production. Sensitivity is provided for gluino and squark masses up to 1.85 TeV and 1.3 TeV respectively. / I denna avhandling presenteras en analys som letar efter supersymmetriska partiklar producerade i proton-proton-kollisioner vid en kollisionsenergi på √s = 13 TeV. Analysen använder sig av data insamlad under 2015 och 2016 av ATLAS-experimentet vid CERNs Large Hadron Collider. Den totala analyserade datamängden motsvarar 36,1 fb−1. Kollisioner som resulterar i par av elektroner eller myoner med motsatt laddning, jets och en stor obalans i rörelsemängd i det transversella planet väljs ut för analys. Målet är att finna tecken på en produktion av skvarkar eller gluiner som sönderfaller till två leptoner och en oladdad supersymmetrisk partikel som lämnar detektorn utan att lämna någon signal. Inom supersymmetriska modeller kan sådana slutliga tillstånd uppkomma genom sönderfallskedjor med Z-bosoner som sönderfaller leptoniskt, eller genom sönderfallskedjor med sleptoner. Flera processer som förutspås av Standardmodellen kan efterlikna den eftersökta signalen och utgör bakgrunder i analysen. De viktigaste bakgrunderna består av Z-bosoner och par av toppkvarkar som produceras direkt i proton-proton-kollisionerna. Dessa bakgrunder uppskattas genom att använda data, medan andra mindre bakgrunder uppskattas genom att använda simuleringar. Ingen signifikant signal utöver den uppskattade backgrunden uppmäts i analysen. Istället tolkas resultaten med hjälp av simuleringar av förenklade supersymmetriska modeller. På så sätt kan exkluderingsgränser med 95% konfidensnivå beräknas för gluino- och skvark-massorna. Massor över 1,85 TeV utesluts för gluiner och massor över 1,3 TeV utesluts för skvarkar. / <p>QC 20180109</p>

This thesis is devoted to a discussion of various aspects of supersymmetric quantum field theories in four and two dimensions. In four dimensions, 𝒩 = 1 supersymmetric quantum gauge theories on various four-manifolds are constructed. Many of their properties, some of which are distinct to the theories on flat spacetime, are analyzed. In two dimensions, general 𝒩 = (2, 2) nonlinear sigma models on S² are constructed, both for chiral multiplets and twisted chiral multiplets. The explicit curvature coupling terms and their effects are discussed. Finally, 𝒩 = (0, 2) gauged linear sigma models with nonabelian gauge groups are analyzed. In particular, various dualities between these nonabelian gauge theories are discussed in a geometric content, based on their Higgs branch structure. / Ph. D.

[Truncated abstract. Formulae and special characters can only be approximated. See PDF version for accurate reproduction.] Theories of self-dual supersymmetric nonlinear electrodynamics are generalized to a curved superspace of 4D N = 1 supergravity, for both the old-minimal and the newminimal versions of N = 1 supergravity. We derive the self-duality equation, which has to be satisfied by the action functional of any U(1) duality invariant model of a massless vector multiplet, and show that such models are invariant under a superfield Legendre transformation. We construct a family of self-dual nonlinear models, which includes a minimal curved superspace extension of the N = 1 supersymmetric Born- Infeld action. The supercurrent and supertrace of such models are explicitly derived and proved to be duality invariant. The requirement of nonlinear self-duality turns out to yield nontrivial couplings of the vector multiplet to Kähler sigma models. We explicitly construct such couplings in the case when the matter chiral multiplets are inert under the duality rotations, and more specifically to the dilaton-axion chiral multiplet when the group of duality rotations is enhanced to SL(2,R). The component structure of the nonlinear dynamical systems introduced proves to be more complicated, especially in the presence of supergravity, as compared with well-studied effective supersymmetric theories containing at most two derivatives (including nonlinear Kähler sigma-models). As a result, when deriving their canonically normalized component actions, the traditional approach becomes impractical and cumbersome. We find it more efficient to follow the Kugo-Uehara scheme which consists of (i) extending the superfield theory to a super-Weyl invariant system; and then (ii) applying a plain component reduction along with imposing a suitable super-Weyl gauge condition. This scheme is implemented in order to derive the bosonic action of the SL(2,R) duality invariant coupling to the dilaton-axion chiral multiplet and a Kähler sigma-model.