993 resultados para Supersymmetric Effective Theories


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The superspace approach provides a manifestly supersymmetric formulation of supersymmetric theories. For N= 1 supersymmetry one can use either constrained or unconstrained superfields for such a formulation. Only the unconstrained formulation is suitable for quantum calculations. Until now, all interacting N>1 theories have been written using constrained superfields. No solutions of the nonlinear constraint equations were known.

In this work, we first review the superspace approach and its relation to conventional component methods. The difference between constrained and unconstrained formulations is explained, and the origin of the nonlinear constraints in supersymmetric gauge theories is discussed. It is then shown that these nonlinear constraint equations can be solved by transforming them into linear equations. The method is shown to work for N=1 Yang-Mills theory in four dimensions.

N=2 Yang-Mills theory is formulated in constrained form in six-dimensional superspace, which can be dimensionally reduced to four-dimensional N=2 extended superspace. We construct a superfield calculus for six-dimensional superspace, and show that known matter multiplets can be described very simply. Our method for solving constraints is then applied to the constrained N=2 Yang-Mills theory, and we obtain an explicit solution in terms of an unconstrained superfield. The solution of the constraints can easily be expanded in powers of the unconstrained superfield, and a similar expansion of the action is also given. A background-field expansion is provided for any gauge theory in which the constraints can be solved by our methods. Some implications of this for superspace gauge theories are briefly discussed.

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Topological interactions will be generated in theories with compact extra dimensions where fermionic chiral zero modes have different localizations. This is the case in many warped extra dimension models where the right-handed top quark is typically localized away from the left-handed one. Using deconstruction techniques, we study the topological interactions in these models. These interactions appear as trilinear and quadrilinear gauge boson couplings in low energy effective theories with three or more sites, as well as in the continuum limit. We derive the form of these interactions for various cases, including examples of Abelian, non-Abelian and product gauge groups of phenomenological interest. The topological interactions provide a window into the more fundamental aspects of these theories and could result in unique signatures at the Large Hadron Collider, some of which we explore.

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We discuss the generalized eigenvalue problem for computing energies and matrix elements in lattice gauge theory, including effective theories such as HQET. It is analyzed how the extracted effective energies and matrix elements converge when the time separations are made large. This suggests a particularly efficient application of the method for which we can prove that corrections vanish asymptotically as exp(-(E(N+1) - E(n))t). The gap E(N+1) - E(n) can be made large by increasing the number N of interpolating fields in the correlation matrix. We also show how excited state matrix elements can be extracted such that contaminations from all other states disappear exponentially in time. As a demonstration we present numerical results for the extraction of ground state and excited B-meson masses and decay constants in static approximation and to order 1/m(b) in HQET.

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Denna studie grundar sig i ett uppdrag från Trafikverket med avsikten att undersöka hur enmångfaldsstrategi kan få ökad effekt i organisationen. Utgångspunkten för denna studie är attdet tycks krävas mer forskning kring hur HR strategiskt kan arbeta med mångfaldsfrågor ochintegrera dem i organisationens alla delar. Syftet med denna studie är således att identifiera hurHR strategiskt kan arbeta med mångfaldsfrågor. Vidare är syftet att visa hur ett strategiskamångfaldsarbete kan bli mer effektivt.Teorier som belyser begreppet mångfald, effekterna av mångfald, strategi, Human ResourceManagement och Strategic Human Resource management kan ses ligga till grund för ettframgångsrikt HRM-arbete med mångfald. Ledarskap, kommunikation, kunskap och att se tillorganisationskulturen belyser teorin som viktiga komponenter för att ett strategiskt arbete skabli mer effektivt och ge effekt i organisationen.Studien bygger på en deduktiv ansats och en kvalitativ metod har genomförts utifrån treindividuella intervjuer och två fokusgrupper. De individuella intervjuernas syfte var att belysaorganisationens nutida arbete med mångfald, framtida perspektiv för hur ett strategisktmångfaldsarbete kan utformas och en målbild för vad arbetet ska resultera i. Den enafokusgruppen bestod av medarbetare från HR från olika regionkontor i landet och hade somsyfte att klargöra hur HR strategiskt kan arbeta med mångfald. Den andra fokusgruppen bestodav chefer från olika regionkontor i landet och hade som syfte att belysa chefers roll och vad deeftersöker i ett strategiskt mångfaldsarbete.Resultatet från intervjuerna har analyserats utifrån den teoretiska referensramen och i dennastudie har vi kommit fram till och identifierat flera betydelsefulla faktorer som för HR är viktigai utformandet av en mångfaldsstrategi. Det är viktigt att definiera begreppet mångfald, klargöraansvarsfrågan, visa på varför organisationen bör arbeta med månglad och kommuniceraeffekterna. Vidare är det viktigt att koppla mångfaldsstrategin till övriga HRM-aktiviteter ochorganisationens övriga strategier och mål för att det strategiska arbetet ska ge effekt. Kunskapom mångfald och att se arbetet som ett förändringsarbete där ledningen utgör en viktig roll harvisat sig vara väsentliga faktorer för att arbetet ska få värde i organisationen.

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The high degree of flexibility has been pointed as one of the outstanding characteristics of the Brazilian job market. Employability is being a frequent discussion issue among the professionals of the human resources area. The Human Capital Theory and the contemporary discussion concerning Employability argue the relationship of the educational practice and of the production practice in a capitalist economical-social structure as a whole. The education consequences in the individuals' life are reflected in several ways, direct and indirectly. Our objective is to evaluate, with statistics methods, and in that universe of consequences, the explanatory events of the relationships between education-wage and education¿job. The main reason of this work is to evaluate the relationship between education, wage and Employability from a structural model perspective, seeking to compare and to contrast two effective theories: the one from the human capital and other from the Employability. To make this analysis, a database of individuals that are working at the formal work market in the Rio de Janeiro Metropolitan Area, had been used. The results showed the education importance on the wage level, as well as, on the Employability factor, whose values and highest taxes correspond to the individuals graduated on the university.

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We use a toy model to illustrate how to build effective theories for singular potentials. We consider a central attractive 1/r(2) potential perturbed by a 1/r(4) correction. The power-counting rule, an important ingredient of effective theory, is established by seeking the minimum set of short-range counterterms that renormalize the scattering amplitude. We show that leading-order counterterms are needed in all partial waves where the potential overcomes the centrifugal barrier, and that the additional counterterms at next-to-leading order are the ones expected on the basis of dimensional analysis. (C) 2008 Elsevier B.V. All rights reserved.

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We discuss the consistency of the traditional vector meson dominance (VMD) model for photons coupling to matter, with the vanishing of vector meson-meson and meson-photon mixing self-energies at q2 = 0. This vanishing of vector mixing has been demonstrated in the context of rho-omega mixing for a large class of effective theories. As a further constraint on such models, we here apply them to a study of photon-meson mixing and VMD. As an example we compare the predicted momentum dependence of one such model with a momentum-dependent version of VMD discussed by Sakurai in the 1960's. We find that it produces a result which is consistent with the traditional VMD phenomenology. We conclude that comparison with VMD phenomenology can provide a useful constraint on such models.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Die vorliegende Arbeit beschäftigt sich mit der Modellierung niederenergetischer elektromagnetischer und hadronischer Prozesse im Rahmen einer manifest lorentzinvarianten, chiralen effektiven Feldtheorie unter expliziter, dynamischer Berücksichtigung resonanter, das heißt vektormesonischer Freiheitsgrade. Diese effektive Theorie kann daher als Approximation der grundlegenden Quantenchromodynamik bei kleinen Energien verstanden werden. Besonderes Augenmerk wird dabei auf das verwendete Zähl- sowie Renormierungschema gelegt, wodurch eine konsistente Beschreibung mesonischer Prozesse bis zu Energien von etwa 1GeV ermöglicht wird. Das verwendete Zählschema beruht dabei im Wesentlichen auf einem Argument für großes N_c (Anzahl der Farbfreiheitsgrade) und lässt eine äquivalente Behandlung von Goldstonebosonen (Pionen) und Resonanzen (Rho- und Omegamesonen) zu. Als Renormierungsschema wird das für (bezüglich der starken Wechselwirkung) instabile Teilchen besonders geeignete complex-mass scheme als Erweiterung des extended on-mass-shell scheme verwendet, welches in Kombination mit dem BPHZ-Renormierungsverfahren (benannt nach Bogoliubov, Parasiuk, Hepp und Zimmermann) ein leistungsfähiges Konzept zur Berechnung von Quantenkorrekturen in dieser chiralen effektiven Feldtheorie darstellt. Sämtliche vorgenommenen Rechnungen schließen Terme der chiralen Ordnung vier sowie einfache Schleifen in Feynman-Diagrammen ein. Betrachtet werden unter anderem der Vektorformfaktor des Pions im zeitartigen Bereich, die reelle Compton-Streuung (beziehungsweise Photonenfusion) im neutralen und geladenen Kanal sowie die virtuelle Compton-Streuung, eingebettet in die Elektron-Positron-Annihilation. Zur Extraktion der Niederenergiekopplungskonstanten der Theorie wird letztendlich eine Reihe experimenteller Datensätze verschiedenartiger Observablen verwendet. Die hier entwickelten Methoden und Prozeduren - und insbesondere deren technische Implementierung - sind sehr allgemeiner Natur und können daher auch an weitere Problemstellungen aus diesem Gebiet der niederenergetischen Quantenchromodynamik angepasst werden.

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Diese Arbeit befasst sich mit der photoinduzierten Erzeugung neutraler Pionen, sehr nahe an der Schwellenenergie. Dabei werden zwei Ziele verfolgt: Zum einen die Überprüfung von Vorhersagen dieser effektiven Theorien und Modelle, zum anderen werden hier erstmals alle relevanten Partialwellenamplituden modellunabhängig aus gemessenen Observablen bestimmt. Diese Methode soll in Zukunft auch bei höheren Energien im Bereich der Nukleonresonanzen Anwendung finden. rnrnKonkret wird die Durchführung und Analyse eines Experiments vorgestellt, welches am Mainzer Mikrotron (MAMI) in den Jahren 2010 bis 2013 mit zirkular polarisiertem Photonenstrahl stattfand. Der Photonenstrahl wurde an einer Anlage zur Erzeugung energiemarkierter Bremsstrahlung aus dem Elektronenstrahl von MAMI gewonnen. Zum Nachweis der Reaktionsprodukte diente das hermetische 4pi CB/TAPS-Detektorsystem. Erstmalig standen bei derartigen Messungen auch transversal polarisierte Protonen zur Verfügung. Dazu wird Butanol in einer speziellen Apparatur dynamisch polarisiert. Molekularer Wasserstoff lässt sich aufgrund der para-Konfiguration nicht polarisieren. Wegen der Verwendung von Butanol als Targetmaterial, bei dem weniger als 5% aller erzeugten Pionen an polarisierten Protonen produziert wurden, ist die Behandlung des Untergrunds eine zentrale Aufgabe. rnrnEs werden zwei Methoden der Untergrundseparation vorgestellt, wovon die bessere in der Analyse angewendet wurde. Abschließend findet eine ausführliche Bewertung systematischer Fehler statt.rnrnDie erstmalige Verwendung transversal polarisierter Protonen ermöglicht den Zugang zu bisher nicht gemessenen Spin"=Freiheitsgraden. In Kombination mit einem komplementären Vorläufer-Experiment aus dem Jahr 2008 mit linear polarisiertem Photonenstrahl konnten aus den gewonnenen Daten erstmals alle komplexen s- und p-Partialwellenamplituden modellunabhängig bestimmt werden. rnrnDarüber hinaus wurden im Rahmen dieser Arbeit wesentliche Verbesserungen am apparativen Aufbau erzielt. Beispiele sind ein Elektronenstrahl-Polarimeter, ein zellularer CB-Multiplizitätstrigger, sowie signifikante Verbesserungen der Datennahmeelektronik und des Triggersystems, die teilweise in dieser Arbeit vorgestellt werden.

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We construct several classes of worldvolume effective actions for black holes by integrating out spatial sections of the worldvolume geometry of asymptotically flat black branes. This provides a generalisation of the blackfold approach for higher-dimensional black holes and yields a map between different effective theories, which we exploit by obtaining new hydrodynamic and elastic transport coefficients via simple integrations. Using Euclidean minimal surfaces in order to decouple the fluid dynamics on different sections of the worldvolume, we obtain local effective theories for ultraspinning Myers-Perry branes and helicoidal black branes, described in terms of a stress-energy tensor, particle currents and non-trivial boost vectors. We then study in detail and present novel compact and non-compact geometries for black hole horizons in higher-dimensional asymptotically flat space-time. These include doubly-spinning black rings, black helicoids and helicoidal p-branes as well as helicoidal black rings and helicoidal black tori in D ≥ 6.

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In her dialogue entitled - Restructuring in the Hospitality Industry - Elisa S. Moncarz, Associate Professor, the School of Hospitality Management at Florida International University, intends for you to know the following: “Recent years have seen a proliferation of restructurings of major American corporations creating an extremely important issue that has affected U.S. business. This article discusses restructuring issues in the hospitality industry, focusing attention on its causes and motivations, as well as on its benefits and perils. The author considers the impact of restructuring on investors and management while examining recent restructurings involving hospitality firms.” In defining the concept of restructuring, Associate Professor Moncarz informs you, “Restructuring entails the implementation of fundamental and comprehensive modification of a company's operational and/or financial structure.” “It has, indeed, become fashionable to take a company apart and put it back together in a different form,” the author says. Additionally, Moncarz refers to a Wall Street Journal study, dated August 1985, which reveals that nearly half the large American corporations were, or were soon to be restructured in the 1984/85 time frame. There are several distinct types of restructurings and the author wants you to be aware of some of them. “…threats of takeover attempts, the larger part of all restructuring have been initiated willingly in order to expand or divest a company's line of business (i.e., operational restructurings) or redirect its finances (i.e., financial restructurings),” the author reveals. “Two principal types of operational restructurings are mergers and acquisitions [M&A], and divestitures [disposing of unwanted units or assets],” Moncarz further defines the concepts of expansion and divestiture. The author explains several types of financial restructuring sketches used in the hospitality industry, including stock re-purchasing, debt issuances and redemptions, swapping debt for equity, and effective theories of realigning debt through extending loans and/or revising terms. To expand their businesses, Moncarz makes anecdotal reference to several major food and beverage corporations that have successfully employed operational restructuring principles. The author wades into the shallow end of the hostile takeover pool by explaining some of the corporate restructuring concepts used to repel that aggressive technique. Walt Disney Company completely redesigned their entire upper level management structure in a successful effort to thwart a hostile takeover bid by corporate raider Saul P. Steinberg, Moncarz informs. To close, the author touches on leveraged buyouts [LBOs], and stock repurchases to divest unwanted divisions and immobilize hostile takeover attempts. A lengthy table of - Selected Restructurings in the Hospitality Industry [1982 to date of article] – is also included.

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Chains of interacting non-Abelian anyons with local interactions invariant under the action of the Drinfeld double of the dihedral group D-3 are constructed. Formulated as a spin chain the Hamiltonians are generated from commuting transfer matrices of an integrable vertex model for periodic and braided as well as open boundaries. A different anyonic model with the same local Hamiltonian is obtained within the fusion path formulation. This model is shown to be related to an integrable fusion interaction round the face model. Bulk and surface properties of the anyon chain are computed from the Bethe equations for the spin chain. The low-energy effective theories and operator content of the models (in both the spin chain and fusion path formulation) are identified from analytical and numerical studies of the finite-size spectra. For all boundary conditions considered the continuum theory is found to be a product of two conformal field theories. Depending on the coupling constants the factors can be a Z(4) parafermion or a M-(5,M-6) minimal model.

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In this work we study the spontaneous breaking of superconformal and gauge invariances in the Abelian N = 1,2 three-dimensional supersymmetric Chern-Simons-matter (SCSM) theories in a large N flavor limit. We compute the Kahlerian effective superpotential at subleading order in 1/N and show that the Coleman-Weinberg mechanism is responsible for the dynamical generation of a mass scale in the N = 1 model. This effect appears due to two-loop diagrams that are logarithmic divergent. We also show that the Coleman-Weinberg mechanism fails when we lift from the N = 1 to the N = 2 SCSM model. (C) 2010 Elsevier B.V All rights reserved.

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In this thesis we study at perturbative level correlation functions of Wilson loops (and local operators) and their relations to localization, integrability and other quantities of interest as the cusp anomalous dimension and the Bremsstrahlung function. First of all we consider a general class of 1/8 BPS Wilson loops and chiral primaries in N=4 Super Yang-Mills theory. We perform explicit two-loop computations, for some particular but still rather general configuration, that confirm the elegant results expected from localization procedure. We find notably full consistency with the multi-matrix model averages, obtained from 2D Yang-Mills theory on the sphere, when interacting diagrams do not cancel and contribute non-trivially to the final answer. We also discuss the near BPS expansion of the generalized cusp anomalous dimension with L units of R-charge. Integrability provides an exact solution, obtained by solving a general TBA equation in the appropriate limit: we propose here an alternative method based on supersymmetric localization. The basic idea is to relate the computation to the vacuum expectation value of certain 1/8 BPS Wilson loops with local operator insertions along the contour. Also these observables localize on a two-dimensional gauge theory on S^2, opening the possibility of exact calculations. As a test of our proposal, we reproduce the leading Luscher correction at weak coupling to the generalized cusp anomalous dimension. This result is also checked against a genuine Feynman diagram approach in N=4 super Yang-Mills theory. Finally we study the cusp anomalous dimension in N=6 ABJ(M) theory, identifying a scaling limit in which the ladder diagrams dominate. The resummation is encoded into a Bethe-Salpeter equation that is mapped to a Schroedinger problem, exactly solvable due to the surprising supersymmetry of the effective Hamiltonian. In the ABJ case the solution implies the diagonalization of the U(N) and U(M) building blocks, suggesting the existence of two independent cusp anomalous dimensions and an unexpected exponentation structure for the related Wilson loops.