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1
Murphy, Kellen J. "Evaluating the Electromagnetic Form Factors of Light Nuclei". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1313510475.
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Gurdogan, Omer Can. "Form factors in superconformal theories in four and three dimensions". Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8190.
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This thesis focuses on form factors in superconformal theories, in particular maximally supersymmetric Yang-Mills (MSYM) and ABJM. Scattering amplitudes in these theories have a wealth of special properties and significant amount of insight has been developed for these along with the modern techniques to calculate them. In this thesis, it is presented that form factors have very similar properties to scattering amplitudes and the techniques for scattering amplitudes can be successfully applied to form factors. After a review of the methods employed, the results for tree-level and multi-loop form factors of protected operators are derived. In four dimensions, it is shown that the tree-level form factors can be computed using MHV diagrams BCFWrelations by augmenting the set of vertices with elementary form factors. Tree and loop-level MHV and non-MHV form factors of protected operators in the stress-tensor multiplet of MSYM are computed as examples. A solution to the BCFW recursion relations for form factors is derived in terms of a diagrammatic representation. Supersymmetric multiplets of form factors of protected operators are constructed. In three dimensions, Sudakov form factor of a protected biscalar operator is computed in ABJM theory. This form factor captures the IR divergences of the scattering amplitudes. It is found that this form factor can be written in terms of a single, non-planar Feynman integral which is maximally transcendental. Additionally, the sub-leading colour corrections to the one-loop four-particle amplitude in ABJM is derived using unitarity cuts. Finally a basis of two-loo pure master integrals for the Sudakov form factor topology is constructed from a principle that relies on certain unitarity cuts.
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Rimal, Dipak. "PROTON FORM FACTOR PUZZLE AND THE CEBAF LARGE ACCEPTANCE SPECTROMETER (CLAS) TWO-PHOTON EXCHANGE EXPERIMENT". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1211.
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Thapedi, Teboho L. "Proton form factors in large NcQCD". Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/6517.
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Includes bibliographical references (leaves 25-26).The proton electromagnetic form factors are obtained using a particular model formula of QCDoo , QCD in the large Nc limit, which sums up the infinite number of zero-width resonances to produce an Euler's Beta function, Dual-QCDoo . The form factors F} (q2), F2(q2) and GM(q2) altogether consistently agree well with reanalyzed space-like data in the whole range of momentum transfer. Additionally, the ratio upGE/GM predictably is in good agreement with recent polarization transfer measurements at Jefferson Lab. The electric and magnetic radii are determined using this current world data.
5
Vitos, Timea. "Electromagnetic form factors of the Sigma*-Lambda transition". Thesis, Uppsala universitet, Kärnfysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392236.
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We introduce and examine the analytic properties of the three electromagnetic transition form factors of the Sigma*-Lambda hyperon transition. In the first part of the thesis, we discuss the interaction Lagrangian for the hyperons at hand. We calculate the decay rate of the Dalitz decay Sigma* Lambda -> e+e- in the one-photon approximation in terms of the form factors, as well as the differential cross section of the scattering e+e- -> Sigma*bar Lambda in the one-photon approximation. In the second part of the thesis, we build up the machinery for calculation of the form factors using dispersion relations, performing an analytic continuation from the timelike, q2 > 0, to the spacelike, q2 < 0, region of the virtual photon invariant mass q2. Due to an anomalous cut in the triangle diagram arising from a two-pion saturation of the photon-hyperon vertex, there is an additional term in the dispersive integral. We use the scalar three-point function as a model for the examination of the dispersive approach with the anomalous cut. The one-loop diagram is calculated both directly and using dispersion relations. After comparison of the two methods, they are found to coincide when the anomalous contribution is added to the dispersive integral in the case of the octet Sigma exchange. By examination of the branch points of the logarithm in the discontinuity, we deduce the structure of the Riemann surface of the unitarity cut and present trajectories of the branch points. The result of our analysis of the analytic structure yields a correct dispersive relation for the electromagnetic transition form factors. This opens the way for the calculation of these form factors in the low-energy region for both space- and timelike q2. As an outlook, we present preliminary calculations for the hyperon-pion scattering amplitude using the unitarity and the anomalous contribution in a once-subtracted dispersion relation. Finally we present the corresponding preliminary unsubtracted dispersive calculations for the form factors.
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Jones, Martyna Maria. "Form factors and scattering amplitudes in supersymmetric gauge theories". Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/53582.
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The study of scattering amplitudes in the maximally supersymmetric Yang-Mills theory (N = 4 SYM) is a thriving field of research. Since the reformulation of perturbative gauge theory as a twistor string theory by Witten, this area has witnessed a flurry of activity, leading to the discovery of a multitude of novel techniques, such as recursion relations and MHV diagrams, collectively referred to as on-shell methods. In parallel, many previously hidden properties and rich mathematical structures have been found, a powerful example of such being the dual superconformal symmetry. It is natural to ask whether this understanding can be extended to phenomenologically relevant theories as well as other quantities. The goal of the present work is to apply the modern on-shell methods to calculations of form factors, with particular focus on those which are relevant for describing Higgs production in QCD from the point of view of an effective field theory. Specifically, our analysis will be carried out in supersymmetric gauge theories at two-loop level and will consist of several steps. We focus first on operators in the SU(2j3) closed subsector of N = 4 SYM, in particular two non-protected, dimension-three operators. We then move on to consider the trilinear operator Tr(F3) and a related descendant of the Konishi operator which contains Tr(F3), also in N =4 SYM. Finally, we concentrate on two-loop form factors of these two operators in theories with less-than-maximal supersymmetry. The result of our investigation shows an emergence of a small number of universal building blocks, ultimately related to the two-loop form factor of a trilinear half-BPS operator. This finding suggests that the most complicated, maximally transcendental part of Higgs plus multi-gluon amplitudes in QCD can be equivalently computed in a remarkably simple way by considering form factors of half-BPS operators in N =4 SYM.
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Bahr, Felix Tobias. "Form factors for semileptonic Bs → Kℓνdecays in lattice QCD". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17384.
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Wir präsentieren eine Forschungsstudie zur Berechnung des Formfaktors f_+(q^2) für den semileptonischen Zerfall B_s -> K l nu in Gitter-QCD-Simulationen im großen Volumen mit zwei dynamischen Seequark-Flavours mit O(a)-verbesserten Wilson-Fermionen. Wir diskutieren die Berechnung relevanter Zwei- und Dreipunkt-Funktionen und betrachten komplementäre Methoden diese zu kombinieren, um den Formfaktor zu erhalten. Insbesondere stellen wir die Strategie eines kombinierten Fits vor, in den Datenpunkte aller Korrelatoren eingehen und der als Fitparameter Energien, Amplituden und den Formfaktor hat. Das b-Quark wird in HQET behandelt; unsere momentane Analyse konzentriert sich auf den statischen Grenzfall. Indes haben wir den Code für alle nötigen O(1/m_h)-Korrekturen entwickelt und die Messungen dieser durchgeführt; sie werden verwendet werden, sobald ihre Koeffizienten von der ALPHA-Kollaboration bestimmt worden sein werden. Um den Formfaktor auf allen Ensembles bei dem gleichen Wert des Impulsübertrags q^2 bestimmen zu können, führen wir getwistete Randbedingungen für das s- und das b-Quark ein, die ein freies Einstellen der Quarkimpulse und damit von q^2 ermöglichen. Wir führen Messungen auf einer Untermenge von N_f=2 CLS Eichkonfigurationen durch und erhalten den Formfaktor bei drei verschiedenen Gitterabständen und etwa gleicher Pionmasse von ungefähr 330 MeV. Wir benutzen diese, um eine Kontinuumsextrapolation durchzuführen, und beobachten, dass diese relativ flach in a^2 ist. Eine Messung bei einer unterschiedlichen Pionmasse deutet an, dass Quarkmassen-Effekte klein sind. Wir vergleichen unseren Kontinuumswert des Formfaktors mit kürzlich veröffentlichten Ergebnissen anderer Kollaborationen und stellen eine gute Übereinstimmung fest.We present an exploratory study of the calculation of the form factor f_+(q^2) for the semileptonic decay B_s -> K l nu in large-volume lattice QCD simulations with two dynamical sea quark flavours using O(a) improved Wilson fermions. We discuss the computation of relevant two- and three-point functions and consider complementary methods how these can be combined to obtain the form factor. In particular, we put forward the strategy of a combined fit in which data of all correlators enter and which has as fit parameters energies and amplitudes of the correlators and the form factor. The b quark is treated in HQET; our present analysis focuses on the static limit. Meanwhile, we have developed the code and performed the measurements of all needed O(1/m_h) corrections which will be used as soon as their coefficients will have been computed by the ALPHA collaboration. In order to be able to measure the form factor at the same value of the momentum transfer q^2 on all ensembles, we impose twisted boundary conditions on the s and b quarks that allow for a free tuning of the quark momenta and thus of q^2. We perform measurements on a subset of N_f=2 CLS gauge configurations, obtaining the form factor at three different lattice spacings and roughly the same pion mass of about 330 MeV. Using these, we carry out a continuum extrapolation and observe that it is relatively flat in a^2. A measurement at a different pion mass indicates that quark mass effects are small. We compare our continuum value of the form factor with recently published results of other collaborations and observe a good agreement.
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Engström, Per-Olov. "Form factors of ω → µ+µ−π0 and ρ → µ+µ− and the dimuon spectrum from NA60". Thesis, Uppsala universitet, Kärnfysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227311.
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Dimuon yields of the decays η → µ + µ − γ, ω → µ + µ − π 0 and ρ → µ + µ − withcalculated form factors by Terschlüsen and Leupold (2010) and Schneider etal. (2012) were numerically fitted to NA60 data and compared to the resultby Arnaldi et al. (2009). The calculated form factors are theoretically moresound and are an alternative to the previously used pole approximation. Inaddition, the ρ production temperature was reviewed theoretically usingthe ratio of η and ω yields. Several fits were made and the best results wereachieved by using Terschlüsen’s form factor for the ω decay and Schneider’sfor the ρ using two fit parameters less than Arnaldi et al. In addition, theassumption that the yield is the result of only three sources could not bedisproved.
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Gulez, Emel. "B meson semileptonic form factors using unquenched lattice QCD". Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155239314.
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Sufian, Raza Sabbir. "DISCONNECTED-SEA QUARKS CONTRIBUTION TO NUCLEON ELECTROMAGNETIC FORM FACTORS". UKnowledge, 2017. http://uknowledge.uky.edu/physastron_etds/49.
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We present comprehensive analysis of the light and strange disconnected-sea quarks contribution to the nucleon electric and magnetic form factors. The lattice QCD estimates of strange quark magnetic moment GsM (0) = −0.064(14)(09) μN and the mean squared charge radius ⟨r2s⟩E = −0.0043(16)(14) fm2 are more precise than any existing experimental measurements and other lattice calculations. The lattice QCD calculation includes ensembles across several lattice volumes and lattice spacings with one of the ensembles at the physical pion mass. We have performed a simultaneous chiral, infinite volume, and continuum extrapolation in a global fit to calculate results in the continuum limit. We find that the combined light-sea and strange quarks contribution to the nucleon magnetic moment is−0.022(11)(09) μN and to the nucleon mean square charge radius is −0.019(05)(05) fm2. The most important outcome of this lattice QCD calculation is that while the combined light-sea and strange quarks contribution to the nucleon magnetic moment is small at about 1%, a negative 2.5(9)% contribution to the proton charge radius and a relatively larger positive 16.3(6.1)% contribution to the neutron charge radius come from the sea quarks in the nucleon. For the first time, by performing global fits, we also give predictions of the light-sea and strange quarks contributions to the nucleon electric and magnetic form factors at the physical point and in the continuum and infinite volume limits in the momentum transfer range of 0 ≤ Q2 ≤ 0.5 GeV2.
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Gayou, Olivier. "Proton form factors : measurement of the proton form factors ratio µP GEp/GMp to Q2 = 5.6 GeV2 by recoil polarimetry". Clermont-Ferrand 2, 2002. http://www.theses.fr/2002CLF22343.
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Dans cette thèse sont présentés les résultats de l'expérience E99-007, qui a mesuré le rapport des facteurs de forme électrique et magnétique du proton, jusqu'au quadri-moment de transfert Q2 = 5. 6 GeV2, par polarisation de recul. Les données ont été prises en 2000 au Thomas Jefferson National Accelerator Facility en Virginie (USA). Un faisceau d'électrons polarisés de 4. 6 Gev a été diffusé sur une cible d'hydrogène liquide. La polarisation du proton de recul était mesurée dans le Polarimètre du Plan Focal, situé à l'extrémité de l'un des deux Spectromètres à Haute Résolution du Hall A. Le rapport des composantes transverse et longitudinale de la polarisation du proton de recul est proportionnel au rapport des facteurs de forme. Les événements élastiques étaient identifiés en détectant l'électron diffusé dans un calorimètre en verre au plomb de grande acceptance. Le résultat principal de cette expérience est la décroissance linéaire du rapport des facteurs de forme quand Q2 augmente, correspondant à des distributions spatiales différentes de la charge électrique et de la magnétisation. De nombreux calculs théoriques montrent que des effets relativistes, comme le mélange des états de spin dûs à des transformations de Lorentz, doivent être pris en compte pour expliquer les résultats observés dans cette région cinématique critique
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Gayou, Olivier. "Proton form factors: Measurement of the proton form factors ratio up to Q(2) = 5.6 GEV(2) by recoil polarimetry". W&M ScholarWorks, 2002. https://scholarworks.wm.edu/etd/1539623396.
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In this thesis, we present the results of the experiment E99-007, which measured the ratio of the electric to magnetic form factors of the proton to the four momentum transfer square Q2 = 5.6 GeV2, by recoil polarimetry. Data were taken in 2000 at the Thomas Jefferson National Accelerator Facility in Virginia, USA. A 4.6 GeV polarized electron beam was scattered off a cryogenic hydrogen target. The polarization of the recoil proton was measured in the Focal Plane Polarimeter, located after one of the two High Resolution Spectrometers in the hall. The ratio of the transverse to longitudinal components of the recoil proton polarization is proportional to the ratio of the form factors. Elastic events were selected by detecting the scattered electron in a large acceptance lead-glass calorimeter.;The main result of this experiment is the linear decrease of the form factor ratio with increasing Q2, corresponding to different spatial distributions of the electric charge and the magnetization. Numerous theoretical calculations show that relativistic effects, such as mixing of spin states due to Lorentz boosts, are important to account for the observed data in this critical intermediate kinematic region.
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Takeyama, Yoshihiro. "Form factors of SU(N) invariant Thirring model". 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149952.
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Gayou, Olivier. "Proton form factors : measurement of the proton form factors ratio mu_pG_Ep/G_Mp to Q^2 = 5.6 GeV^2 by recoil polarimetry". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2002. http://tel.archives-ouvertes.fr/tel-00001674.
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Dans cette thèse sont présentés les résultats de l'expérience E99-007, qui a mesuré le rapport des facteurs de forme électrique et magnétique du proton, jusqu'au quadri-moment de transfert Q2 = 5.6 GeV2, par polarisation de recul. Les données ont été prises en 2000 au Thomas Jefferson National Accelerator Facility en Virginie, Etats-Unis. Un faisceau d'électrons polarisés de 4.6 GeV a été diffusé sur une cible d'hydrogène liquide. La polarisation du proton de recul était mesurée dans le Polarimètre du Plan Focal, situé à l'extrémité de l'un des deux Spectromètres à Haute Résolution du Hall A. Le rapport des composantes transverse et longitudinale de la polarisation du proton de recul est proportionnel au rapport des facteurs de forme. Les événements élastiques étaient identifiés en détectant l'électron diffusé dans un calorimètre en verre au plomb de grande acceptance. Le résultat principal de cette expérience est la décroissance linéaire du rapport des facteurs de forme quand Q2 augmente, correspondant à des distributions spatiales différentes de la charge électrique et de la magnétisation. De nombreux calculs théoriques montrent que des effets relativistes, comme le mélange des états de spin dûs à des transformations de Lorentz, doivent être pris en compte pour expliquer les résultats observés dans cette région cinématique critique.
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Robards, Simon William Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "The hydrodynamics of high-speed transom-stern vessels". Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/42782.
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In the design of all marine craft the prediction of a vessel??s resistance characteristics is a major consideration. The accurate prediction of resistance is particularly important in the design of modern high-speed vessels where the primary contractual obligation placed upon the builder is the vessel??s achievable speed. Investigation was made of the methods of Doctors and Day, whereby the traditional Michell wave-resistance theory, published in 1898, is improved on through a better understanding of the hydrodynamics of transom sterns and the application of statistically determined form factors. One of the difficulties with the Michell theory is how to account for the hollow that forms behind a transom stern, a feature prevalent in high-speed vessels. A common approach in the numerical prediction of wave resistance for transom-stern vessels is to discretize the hollow as a geometrically-smooth addition to the vessel. Therefore, of great importance in accurate prediction of wave resistance is the hydrodynamics of, and in particular, the length and depth of the hollow formed behind the transom stern. Accordingly, a systematic series of transom-stern models were tank tested at various drafts and speeds in order to determine experimentally the length and depth of the hollow as a function of vessel speed, draft and beam. From the experimental data, algorithms for the determination of the length and depth of the transom hollow, have been developed and utilised in the discretization of the transom hollow for prediction of resistance using the Michell wave- resistance theory. Application of the developed hollow algorithms produced significant improvements in correlation of the experimental and theoretical predictions of total resistance, particularly in the lower Froude range. In addition to the transom-hollow investigation, form factors were obtained using least-squares regression of existing experimental data. The form factors were based on the major geometric parameters of the models used. In the research presented here, the method was applied to a large range of published resistance data for high-speed displacement vessels. Considerable improvement in correlation, between theoretical and experimental predictions of total resistance, was obtained by incorporating the calculated form-factors into the total resistance formulation.
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Elghazali, Burhan. "Urban Intensification in Metropolitan Khartoum : Influential Factors, Benefits and Applicability". Doctoral thesis, KTH, School of Architecture and the Built Environment (ABE), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4040.
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This dissertation explores the theoretical and methodological implications involved in the policy framework needed to intensify urban residential areas in a developing country. Metropolitan Khartoum, Sudan, has been chosen as a case study. The aim of the study is to further our understanding of the implications of transforming a sprawling city form to an intensified form. The objectives are: to identify the factors that have shaped Sudanese urban form in general and Metropolitan Khartoum in specific; to identify the policies that can intensify the urban residential neighborhoods in Metropolitan Khartoum; and, to influence both the demand and requisite housing needs for this intensified form. This research is qualitative in its nature: the complexity of the study problematic required the adoption of a constructivist paradigm as the fundamental set of beliefs. Inductive arguments are used in conjunction with a wide range of methods, including detailed descriptions of Sudan and metropolitan Khartoum, with special emphasis on how local environment, urban challenges, policy, legislation and practices affect the study problematic. The theoretical premises of intensification are reviewed along with development issues, urban infrastructure challenges and opportunities in developing countries and local acceptability of intensification. The different forces that can shape urban forms have been described and the suitability of metropolitan Khartoum, with different general urban intensification policies and practices and of urban management tools in large African cities has been investigated. The outcome of the study provides detail for a discussion of results that work to explain some of the cause and effect of urban sprawl in Metropolitan Khartoum. It also suggests possible change in both policy and regulation to induce successful city reform towards intensification.
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Belushkin, Maxim. "Dispersion theoretical analysis of the nucleon electromagnetic form factors". [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=984865993.
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Willetts, Jennifer. "Approaches to form-factors of higher spin Heisenberg chains". Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3114.
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In this thesis we apply the vertex operator approach of Jimbo and Miwa to higher spin Heisenberg chains with the aim of computing the form-factors of these quantum integrable models. The work is motivated by the relation of the form-factors to the dynamical structure factors of the model - objects that are experimentally realisable - and potential for comparison with real-world results. Using a one boson, one fermion free field realisation of Uq(sl2), in conjunction with a realisation for the fermionic contribution due to Shiraishi, we are able to give the formalism required to obtain explicit multiple integral expressions for the 2m-particle form-factors of the antiferromagnetic spin-1 Heisenberg chain. Using this novel boson-fermion-Shiraishi scheme, we are able to obtain single integral expressions for the two-spinon contribution to the S+ form-factor. We also consider a certain modification of a known q-Wakimoto bosonisation scheme for arbitrary spin and its relevance to the computation of higher spin form-factors. We consider the form of the resultant BRST relations and discuss simplifications arising through this approach, as well as the difficulties faced in obtaining integral expressions.
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Le, Bohec Mickaël. "Contribution du rayonnement au confort thermique et aux économies d'énergie dans l'habitat". Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0029/document.
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Pour réduire la consommation énergétique des bâtiments, les systèmes de chauffage agissant par rayonnement semblent particulièrement intéressants puisqu'ils ne nécessitent pas de chauffer l'air de la pièce pour que leur action soit perçue (moins d'énergie dépensée et moins de déperditions) et qu'jls permettent une meilleure réactivité au mode de vie des utilisateurs. De plus, des expériences réalisées au MIT ont montré que nous préférons un air frais et des murs chauds plutôt que le contraire, ce qui milite en paveur du chauffage par rayonnement. L'objectif de ce travail est de développer un outil permettant de paire le lien entre le rayonnement échangé entre un occupant et son environnement et le confort qu'il exprime vis-a- vis de celui-ci. L'étude des transferts radiatifs dans l'habitat peut se ramener a la résolution de l'équation des radiosités. Celle-ci nécessite l'évaluation de couplages géométriques entre les éléments de la scène appelés facteurs de forme. Leur obtention est particulièrement ardue, notamment lorsqu'il s'agit de tenir compte d'éventuelles obstructions. Une comparaison des méthodes numériques disponibles pour cela est proposée. Outre l'évaluation de ces facteurs, le système a résoudre est très lourd, puisque chaque surface interagit, le plus souvent, avec toutes les autres et que le nombre de nœuds mis en jeu dans la description d'une scène complexe est important. Nous présentons une méthode de résolution qui raffine le maillage d'une scène tout en construisant simultanément une représentation a différentes échelles des facteurs de forme entre ses éléments, dans le but de ne pas calculer tous les échanges a la résolution la plus fine. Elle permet ainsi de réduire considérablement le temps de calcul et rend son utilisation possible en bureau d'étude.une fois que les transferts radiatifs entre un individu, la source de chauffage et différents éléments de l'environnement sont connus, le modèle de confort de Fanger est mis en oeuvre pour déterminer si les configurations envisagées sont confortables ou non, au regard des normes en vigueur dans le bâtiment. Ainsi, nous avons pu déterminer quels types d'appareils de chauffage sont les plus susceptibles d'apporter du confort, dans diverses situations, et sans accroitre la puissance consomméeIn order to reduce building's energy consumption, radiant heater seems particularly attractives because they didn't require to heat the air of the room to be perceived (less energy spent and less losses), and because they provide a better reactivity to users life rythmes. Moreover, experiences of the MIT showed that we prefer a fresh ai with warm wall rather than the opposite. The goal of the work is to develop a tool to study the link between the radiant energy exchange by an occupant with his environment and the thermal comfort express under some hypothesis, radiative beat transfers can be idealized by the radiosity equation. This one needs the evaluation of geometrics couplings between the elements of the scene called form factors or view factors. It's generally hard to get them, especially when there are obstructions. A comparison of existing numerical methods is proposed. beyond the evaluation of those factors, the algebraic system is heavy to solve because each surface interact, usually, with all the others and because the number of nodes required for the description of a complexe scene is important. We present a resolution method which refine the mesh of the scene while constructing a multi scale representation of form factors between its elements, in order to don't have to compute all the transfers at the finest resolution. This drastically reduce the computation time and allow to use this method in a industrial development process.When the radiative transfers between the occupant, heaters and differents elements of the environment are known, the thermal comfort model of fanger is used to determine if the considered env!ronments are confortable or not, according to international standards. This way, we could find which type of heaters are the most subject to provide thermal comfort without increasing energy consumption
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Lee, Jae Choon. "The Effects of Urban Form on Vehicle Emissions - Focusing On Urban Form Factors and Three Conventional Air Pollutions and Carbon Dioxide -". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354657016.
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Paulus, Timo. "Soft diffractive high energy scattering and form factors in nonperturbative QCD". [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966005023.
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Sanchez-Puertas, Pablo [Verfasser]. "A theoretical study of meson transition form factors / Pablo Sanchez-Puertas". Mainz : Universitätsbibliothek Mainz, 2016. http://d-nb.info/1121819184/34.
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Ikizlerli, Nehir. "Quark and gluon form factors at three loops in perturbative QCD". Thesis, Durham University, 2009. http://etheses.dur.ac.uk/118/.
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We compute the quark and gluon form factors at up to three-loop order within massless perturbative Quantum Chromodynamics by studying the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons. We use Feynman diagram methods to derive expressions for the form-factors in terms of tensor loop integrals in $D=4-2\epsilon$ dimensions. We review various methods for relating tensor integrals to a basis set of master integrals and utilize the FIRE package based on Integration-By-Parts to perform the reduction, thereby enabling the form factors to be expressed (in $D$-dimensions) as a sum of master integrals. We assemble the known results for master integrals and use them to provide a Laurent expansion in $\epsilon$ through to $\mathcal{ O}(\epsilon^{0})$. The results for the three-loop form factors may provide the building blocks for many third-order cross section calculations.
24
Green, Jeremy, Nesreen Hasan, Stefan Meinel, Michael Engelhardt, Stefan Krieg, Jesse Laeuchli, John Negele, Kostas Orginos, Andrew Pochinsky i Sergey Syritsyn. "Up, down, and strange nucleon axial form factors from lattice QCD". AMER PHYSICAL SOC, 2017. http://hdl.handle.net/10150/624681.
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We report a calculation of the nucleon axial form factors G(A)(q)(Q(2)) and G(A)(q)(Q(2)) for all three light quark flavors q is an element of{u, d, s} in the range 0 <= Q(2) less than or similar to 1.2 GeV2 using lattice QCD. This work was done using a single ensemble with pion mass 317 MeVand made use of the hierarchical probing technique to efficiently evaluate the required disconnected loops. We perform nonperturbative renormalization of the axial current, including a nonperturbative treatment of the mixing between light and strange currents due to the singlet-nonsinglet difference caused by the axial anomaly. The form factor shapes are fit using the model-independent z expansion. From G(A)(q)(Q(2)), we determine the quark contributions to the nucleon spin and axial radii. By extrapolating the isovector G(P)(u-d)(Q(2)), we obtain the induced pseudoscalar coupling relevant for ordinary muon capture and the pion-nucleon coupling constant. We find that the disconnected contributions to G(P) form factors are large, and give an interpretation based on the dominant influence of the pseudoscalar poles in these form factors.
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Barnett, Michael A. "Weak electron scattering for the 3He-3H transition and the weak nuclear form factors". FIU Digital Commons, 1995. http://digitalcommons.fiu.edu/etd/1398.
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We calculate the differential cross section for weak electron scattering reaction, e + 3He-' 3H + ve, for energies from 100 MeV to 6 GeV as a function of outgoing nucleus angle from 0 to n/2 radians. We find that the differential cross section at low [q2] increases with electron energy from 0.1 GeV to 6.0 GeV, such that the peak value at 6.0 GeV is approximately 3.2 x 10-40 cm 2 / ster, a factor of 10 larger than the peak value at 0.1 GeV. We also find that the width of the peak falls very rapidly with increasing electron energy. At high [q2] we find that the differential cross section falls by approximately three orders of magnitude making experimental observation at this time unlikely. The contributions of the individual form factors are obtained for electron energies of 0.5GeV and 2.0 GeV. It is found that at low [q2] the form factors, FA(q2) and Fv(q2), make contributions of similar size to the differential cross section and might be simultaneously determined , but for the case of FM(q2) we find that the contribution is too small to determine. It is also found that at large [q2] values, the contribution of FM(q2) is substantially enhanced , but that the cross section is probably too small to enable a direct determination of FM(q2).
26
Bharucha, Aoife Katy Manek. "B → K∗µ+µ− and form factors for semi-leptonic and radiative B decays". Thesis, Durham University, 2010. http://etheses.dur.ac.uk/486/.
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The hadronic environment of the LHC favours the study of exclusive modes, and of these semi-leptonic and radiative B decays will play a leading role in the search for new physics (NP). A prime example is the rare decay B→K∗(→ Kπ)µ+µ−, where the many measurable quantities offer important new tests of the Standard Model and its extensions. We define sets of CP-conserving and CP-violating observables which are studied in terms of the full form factors, calculated in QCD sum rules on the light-cone (LCSR), and QCD factorisation. Those with reduced dependence on hadronic quantities and sensitivity to NP are identified. In the first few years of data–taking at the LHC, the focus will be on quantities which are simple to extract while maximising the available NP sensitivity. Out of three such observables, two are well known to the experimental community. However a third, one of the CP-conserving angular observables, leads to significant additional constraints on parameter space. We then study form factors for rare semi-leptonic and radiative B decays to K(∗) , ρ and φs mesons, combining theoretical and phenomenological constraints from Lattice QCD, LCSR, and dispersive bounds. We pay particular attention to form factor parameterisations which are based on the so-called series expansion, and study the related systematic uncertainties on a quantitative level. Finally we calculate the leading-twist O(αsβ0) corrections to the B → π transition form factor f+ (0) in LCSR, allowing an improved determination of the CKM matrix element |Vub |.
27
Lolli, Linda. "Prolegomena for a comparative study of correlation functions in 2D integrable field theories". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18144/.
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Questo lavoro di tesi si concentra sulla teoria dei Form Factors di operatori locali in due dimensioni. Si espone innanzitutto la teoria dello scattering fattorizzato, propria dei sistemi integrabili, per poi trattare sia classicamente che quantisticamente due modelli integrabili massivi, Sine-Gordon e Sinh-Gordon. Viene esposta l'algebra di Faddeev-Zamolodchikov, per mezzo di cui è possibile trovare lo spazio di Hilbert per modelli integrabili come spazio delle sue rappresentazioni. L'attenzione è infine posta sul regime in cui l'ampiezza relativa alla riflessione solitone-antisolitone nella matrice di scattering è nulla; tale caso si ottiene per valori particolari della costante di accoppiamento del modello di Sine-Gordon, coincidenti con i valori di soglia degli stati legati. Due proposte per l'espressione dei form factors per solitoni sono state prese in considerazione, avanzate una da Lukyanov, l'altra da Babelon, Bernard e Smirnov, tentando un confronto.
28
Silva, António. "Form factors of the baryon octet in the chiral quark soliton model". [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972728074.
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Knödlseder, Michael [Verfasser], i Vladimir [Akademischer Betreuer] Braun. "Nucleon electromagnetic form factors in perturbative QCD / Michael Knödlseder. Betreuer: Vladimir Braun". Regensburg : Universitätsbibliothek Regensburg, 2015. http://d-nb.info/1075050324/34.
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30
Poor, Jennifer L. "Nucleon axial vector form factors and electromagnetic transition amplitudes in perturbative QCD". W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539623800.
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Values for the normal isovector axial vector form factor g$\sb{\rm A}$(Q$\sp2$) are calculated from the leading order perturbative QCD hard scattering amplitude and some previously reported models for the nucleon distribution amplitude, some of which have been derived from QCD sum rules. The values obtained from each of the distribution amplitudes gives a result that is consistent with the data extrapolated to high momentum transfer. The axial vector form factor is around one and one half times the proton's magnetic form factor in all the models which is also in accord with the data. We also calculate the isoscalar axial vector form factor G$\sbsp{\rm A}{\rm (S)}$(Q$\sp2$). Again we calculate the hard scattering amplitude to leading order in perturbative QCD and convolute that with various models for the nucleon distribution amplitude. There is no data at the present time with which to compare the resulting form factors; however, there is interest in knowing the value since the isoscalar axial vector form factor plays a role in some nonstandard weak interaction models. We find the result to be about half of that for the isovector axial vector form factor. The nucleon-delta electromagnetic transition amplitude is calculated using the same method as in the other cases. However, in this case, the hard scattering amplitude is known, and we use the method of QCD sum rules to develop a model for the delta distribution amplitude. We use these results with the same nucleon distribution amplitudes to get a value for the transition amplitude. We also carry out the same calculation for the lowest-lying negative parity states with both isospin one-half which corresponds to the S$\sb{11}$(1535) and isospin three halves. Compared to the results for the nucleon, the delta, and both the higher-mass negative parity cases are less asymmetric with the isospin three-halves states being consistent with the asymptotic form. The results for the nucleon-delta transition amplitude are found to be consistent with the available data as are the results for the nucleon-S$\sb{11}$(1535) transition amplitude.
31
Barcus, Scott Kevin. "Extraction and Parametrization of Isobaric Trinucleon Elastic Cross Sections and Form Factors". W&M ScholarWorks, 2019. https://scholarworks.wm.edu/etd/1563898943.
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By mining data from Jefferson Lab Hall A experiment E08-014 a new measurement of the 3He elastic cross section at Q^2 ≈ 34 fm^−2 was extracted from a large quasielastic background. This new data point falls approximately halfway between the first and second diffractive minima of the 3He form factors. When combined with recent high Q^2 3He elastic cross section measurements from JLab this new point improves our knowledge of the cross section and form factors at large momentum transfers. The new high Q^2 data motivate a reanalysis of the 3He elastic cross section world data and promise an improved understanding of the magnetic form factor in particular. For this analysis the elastic cross section world data for 3He, and its mirror nuclei 3H, were collected. The world data spans five decades and many different experimental facilities. The world data were then fit using a sum of Gaussians parametrization which allowed for the extraction of both targets’ magnetic and electric form factors, along with charge densities and radii. These new fit results were contrasted with past fit results and compared to modern theoretical predictions.
32
Montané, March M. Amor. "Terminologia i implantació : anàlisi d'alguns factors que influencien l'ús dels termes normalitzats de la informàtica i les TIC en llengua catalana". Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/97295.
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En aquesta tesi es duu a terme una anàlisi de la implantació de la terminologia en l’ús amb l’objectiu de trobar les causes que expliquen l’èxit o el fracàs de les propostes denominatives. Partim de la premissa que existeix un conjunt de factors que influencien positivament o negativament la implantació terminològica. En aquest treball estudiem la implantació en l’ús de la terminologia normalitzada de l’àmbit de la informàtica i les tecnologies de la informació i la comunicació (TIC) en un corpus especialitzat. Establim una metodologia de treball que ens permet d’obtenir dades quantitatives i qualitatives per a la recerca de factors d’implantació i, a continuació, ens proposem d’estudiar-ne alguns, que tenen a veure amb aspectes lingüístics (brevetat de les denominacions i acostament formal i semàntic amb el terme original), socio¬lingüístics (àmbit d’ús de la terminologia, via d’entrada dels termes en un àrea temàtica determinada i concurrència terminològica) i procedimentals (difusió dels termes a través de diccionaris generals i especialitzats). L’anàlisi ens proporciona dades empíriques per confirmar que alguns dels aspectes àmpliament tractats en la bibliografia són efectivament factors d’implantació.This work presents a terminology implantation analysis with the aim to find the causes explaining the success or failure of terms in real language use. We depart from the premise that there are factors which influence terminology implantation in a positive o negative way. Our study analyses the implantation of standardised terms of Computer Science and Information and Communication Technologies (ICT) in a specialised corpus. We establish a specific methodology in order to obtain quantitative and qualitative data for the research of implantation factors. In this work we study some of these factors, especially those related with linguistic aspects (brevity of terms and formal and semantic proximity to the original term), sociolinguistic aspects (field of use, entry of terms in a specific domain and terminological competition) and procedural aspects (term dissemination through general and specialised dictionaries). The results obtained provide empirical data to confirm some of the aspects widely discussed in the literature as real implantation factors.
33
Chesteen, Donna Marie. "Experimenting with the finite element method in the calculation of radiosity form factors". Master's thesis, University of Central Florida, 1995. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/22984.
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University of Central Florida College of Arts and Sciences ThesisRadiosity has been used to create some of the most photorealistic computer-generated images to date. The problem, however, is that radiosity algorithms are so computationally and memory expensive that few applications can employ them successfully. Form factor calculation is the most costly part of the process. This report describes an algorithm for using the finite element method to reduce the amount of time that is used in the form factor calculation portion of the radiosity algorithm. This technique for form factor claculation significantly reduces the number of projections done at each iteration by using shape functions to determine the distribution of a form factor acrosst he surface of a patch and thus greatly reduces total run time.
M.S.;
Computer Science;
Arts and Sciences;
Computer Science;
77 p.
vii, 77 leaves, bound : b ill. ; 28 cm.
34
Schneider, Sebastian [Verfasser]. "Analysis tools for precision studies of hadronic three-body decays and transition form factors / Sebastian Schneider". Bonn : Universitäts- und Landesbibliothek Bonn, 2013. http://d-nb.info/1044868813/34.
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Zarnauskas, Gabriel Rocha de Santana. "Determinação de alguns parâmetros da teoria de perturbação quiral". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-10012011-175739/.
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A teoria de perturba ca o quiral (ChPT) e aceita, atualmente, como a teoria efetiva da cromodinamica quantica (QCD) para baixas energias. Ela foi colocada na sua versa o moderna com os artigos de Gasser e Leutwyler, na primeira metade da d ecada de 80 e, durante os 25 anos que se seguiram, ocorreu um aumento considera vel da variedade de fenomenos por ela descritos, sempre acompanhando a precisa o cres- cente dos resultados experimentais. Os trabalhos que apresentamos nesta tese de doutorado se inserem neste contexto e envolvem duas partes, ambas relacionadas a` determina c ao de alguns dos parametros que compo em a lagrangiana da ChPT. Por ser uma teoria efetiva, tais constantes s o podem ser fixadas por experimentos, modelos ou por c alculos da QCD na rede. Em um dos trabalhos, discutimos a cons- tante de decaimento do p on, F, e os efeitos decorrentes do acr escimo de intera co es eletromagn eticas a` ChPT. N os argumentamos que as incertezas estimadas para o valor mais aceito de F podem estar subestimadas. Mostramos, tamb em, que na o se pode determinar esta constante na presen ca das intera co es eletromagn eticas, pois a grandeza de onde ela e extra da adquire uma dependencia no calibre utilizado no ca lculo e tem suas propriedades alteradas drasticamente. No outro trabalho, abor- damos os fatores de forma escalares dos m esons pseudoescalares em tres sabores. A partir dos resultados obtidos com a ChPT e do uso de um modelo que trata dos fatores de forma no espa co das posi co es, conseguimos escreve-los em termos ape- nas das constantes presentes na lagrangiana em ordem dominante da ChPT, F e as massas dos m esons pseudoescalares. No s determinamos, tamb em, os respectivos raios quadra ticos m edios e, comparando-os com os calculados com a ChPT, obtive- mos as LECs L4(mu) = -0,26 · 10^-3 e L5(mu) = 0,85 · 10^-3, para mu = 770 MeV. Esses valores sa o compat veis com as principais estimativas vindas da ChPT.At present, chiral perturbation theory (ChPT) is considered the effective theory of quantum chromodynamics (QCD) at low energies. It was established in its modern version by the papers of Gasser and Leutwyler written in the first half of the 80s. For the last 25 years, there has been considerable increase in the number of phe- nomena described by ChPT, always following the growing precision of experiments. The two works we present in this Ph.D. thesis are related to ChPT and discuss the determination of some of the parameters that appear in the ChPT lagrangian. As ChPT is an effective theory, such constants can only be fixed by experiments, models or calculations in the lattice. In the first presented work, we discuss the pion decay constant, F, and how it is changed by the inclusion of electromagne- tic interactions. We argue that the uncertainty of the most accepted value of F might be underestimated. We also show that we cannot determine this constant in the presence of electromagnetic interactions because the function from which it is extracted acquires a gauge dependence and the functions properties drastically change. In the other work, we deal with pseudoscalar meson scalar form factor in three flavors. We manage to write the form factors only in terms of constants present in ChPT lagrangian at leading order, F and masses of pseudoscalar mesons, using ChPT results and the model that deals with form factors in coordinate space. We also determine the respective square radii and, comparing these to those calculated using ChPT, we have obtained L4(mu) = -0.26 · 10^-3 and L5(mu) = 0.85 · 10^-3, for mu = 770 MeV. These values are compatible with the main estimates evaluated with ChPT.
36
Jones, Gareth W. "Meson distribution amplitudes : applications to weak radiative B decays and в transition form factors". Thesis, Durham University, 2007. http://etheses.dur.ac.uk/2926/.
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This thesis examines the applications and determinations of meson light-cone distribution amplitudes, which enter the theoretical description of exclusive processes at large moment urn transfer. The investigation of such processes, in the context of в physics, provides one with a rich and extensive way of determining the Standard Model parameters of the CKM matrix, which are essential in describing CP violation, and searching for tell-tale signs of new physics beyond the Standard Model. We investigate the twist-2 and twist-3 distribution amplitudes of vector mesons and fully examine SU(3)(_F)-breaking effects and include leading G-parity violating terms. We use the conformal expansion allowing the distribution amplitudes to be described by a set of non-perturbative hadronic parameters which is reduced by invoking the QCD equation of motion to find various interrelations between the distribution amplitudes. Numerical values of the leading non-perturbative hadronie parameters are determined from QCD sum rules. The new distribution amplitude results find direct application in the radiative B decays to light vector mesons B → Vγ. We examine the phenomenologically most important observables in this decay mode using the formalism of QCD factorisation in which the distribution amplitudes play a vital role. We also include long-distance photon emission and soft quark loop effects, which formally lie outside the QCD factorisation formalism. The analysis encompasses all the relevant modes, that is B(_u),(_d)→(_p),(_w),K* and B(_s) → φ,K*.We also calculate the B → n(^1) transition form factor using QCD sum rules on the light- cone. The method relies on the collinear factorisation of the QCD dynamics into a pertur- batively calculable hard-scattering kernel and the non-perturbative universal distribution amplitudes. We include the singlet contribution originating from the U(1)a anomaly and bring the calculation consistently within the n-n(^1) mixing framework.
37
Al-Shamali, Mansour. "Weak form efficiency and factors leading to market efficiency in the Kuwait stock market". Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/6735.
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A small stock market may be less efficient in the weak sense than a large one, because it is often less elaborately organised technically. Hence, information about stock price formation may spread only gradually through the financial community. Consequontly, stock prices may display e greeter degree of nonrandomness because traders are unable to eliminate this. The objective of the study is to test the weak form efficiency in Kuwait Stock Exchange, a segment of the Kuwait Long Term capital market. In addition, the study explores the impact of several. factors on market efficiency. In Chapter One the role of the stock market and its relationship to the economy will be discussed. The efficient market hypothesis is explored in Chapter Two. Chapter Three is devoted to surveying the empirical findings of other researchers in UK, USA and some other international markets. A number of authors have applied the efficient market hypothesis to actual stock market data, especially in the last twenty years. Some critical analyses are discussed in Chapter Four. The empirical question of the relations between market efficiency and stock valuation is explored in Chapter Five. An efficient market should price the security, so as to fully reflect the firms earning power. The uncertainty surrounding the stream of future income clouds this issue and has prompted debate among economists and financial analysts as to how the market values a given stock at any time. The characteristic of Kuwait Stock Exchange are the subject of Chapter Six. Chapter Seven presents empirical findings on the behaviour of Kuwait Stock Exchange in the context of efficient market theory. These findings will be compared with those related studies based on data from the United States and Europe. Chapter Eight will discuss the Kuwait Gulf Stock Exchange (over-the- counter market) or Al-Manakh. The 1982 crash of Al-Manakh is explored in depth in Chapter Nine and some of the important solutions will be discussed. In Chapter Ten the discussion Focusses on the three hypothesised Factors leading to market efficiency (market information, governmental rules and regulations, and market support facilities). Finally, in Chapter Eleven, general conclusions are drawn and recommendations presented with suggestions for further research.
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Pedroso, de Lima Hugo. "Lattice QCD calculations of Kl3 and pion form factors using partially twisted boundary conditions". Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/205469/.
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This thesis presents results of lattice QCD computations of the K → π semi-leptonic (Kl3) and pion electromagnetic form factors using partially twisted boundary conditions. These form factors parameterize low-energynon-perturbative strong interaction effects and cannot therefore be calculated in perturbative QCD. The pion electromagnetic form factor provides information on its charge distribution. The Kl3 form factor at zero momentum transfer (q2 = 0) can be used in the determination of the |Vus| element of the CKM matrix. An accurate determination of these form factors is therefore important. Using partially twisted boundary conditions we calculate the Kl3 form factor directly at q2 = 0, removing the need for the q2 interpolation required in previous lattice QCD simulations, thus eliminating one source of systematic error in this calculation. We also use partially twisted boundary conditions to calculate the pion form factor at values of q2 close to q2 = 0 allowing for a direct evaluation of the charge radius of the pion. The simulations are performed on an ensemble of the RBC/UKQCD collaboration’s gauge configurations with Domain Wall Fermions and the Iwasaki gauge action with an inverse lattice spacing of 1.73(3) GeV at light quark masses corresponding to a pion mass of 330 MeV. We calculate the form factors at these simulated quark masses and then use chiral perturbation theory to extrapolate our results to physical light quark masses. We find for the charge radius of the physical pion fir2π fi = 0.418(31) fm2, in agreement with the experimentally determined result. For the value of the Kl3 form factor, fKπ + (q2), at q2 = 0 and physical quark masses we find fKπ + (0) = 0.960(+5 −6). This result is then used to determine a value for |Vus|. Together with a recent determination of |Vud| we find that the current results are consistent with unitarity of the CKM matrix
39
Hanyok, Lauren Watson. "Methods for Calculating Motion Induced Interruptions as Applied to a Space Capsule After Splashdown". Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/19252.
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The introduction of calculation methods for motion induced interruptions (MII) in 1984introduced a new way to quantify human factors in addition to the motion sickness index
(MSI). The 1990 Graham method for calculating MII uses a combination of a vessel\'s
acceleration and roll to determine a tipping" factor to calculate MII per minute. The
Applebee-Baitis (AB) method considered that the motions are implicitly considered in accelerations, and therefore did not require roll to calculate MII. This thesis examines and
analyzes the di"erences between the AB and Graham methods and compares their results
for a unique hull form shape, a cylindrical capsule, in rough seas to determine which method
is preferred. Two tests were performed by the Naval Surface Warfare Center, Carderock
Division (NSWCCD) for the National Aeronautics and Space Administration (NASA) on
the Orion Crew Exploration Vehicle (CEV) in post-splashdown conditions. A one-quarter
scale model of the CEV was tested at the Aberdeen Test Center in Aberdeen, Maryland.
Direct comparison of the analyzed data, MII sensitivity to location, and scaling analyses are
examined and future work to further the application of MII calculation methods are proposed.
The symmetry of the capsule leads to the assumption that roll and pitch-dominant
MII calculations should be on the same order of magnitude. They are not because both MII
methods only take roll-motions into account. The inclusion of both pitch and roll motions
for the MII calculations is proposed as future work. The Graham method was found to be
the more appropriate calculation because it is more conservative, and therefore preferred in
the context of crew safety.
Master of Science
40
Emmerich, Maximilian [Verfasser], i Andreas [Akademischer Betreuer] Schäfer. "Decay Form factors for Λb,c and B with QCD sum rules / Maximilian Emmerich ; Betreuer: Andreas Schäfer". Regensburg : Universitätsbibliothek Regensburg, 2018. http://d-nb.info/1166950751/34.
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Koster, Laura Rijkje Anne. "Form factors and correlation functions in N=4 super Yang-Mills theory from twistor space". Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18057.
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Das Standardmodell der Teilchenphysik hat sich bis heute, mit Ausnahme der allgemeinen Relativitätstheorie, als erfolgreichste Theorie zur Beschreibung der Natur erwiesen. Störungstheoretische Rechnungen für bestimmte Mengen in Quantenchromodynamik (QCD) haben bisher unerreicht präzise Vorraussagen ermöglicht, die experimentell nachgewiesen wurden. Trotz dieser Erfolge gibt es Teile des Standardmodells und Energieskalen bei denen die Störungstheorie versagt und man nach Alternativen suchen muss. Vieles können wir hierbei verstehen, indem wir eine ähnliche Theorie untersuchen, die sogenannte planare N=4 Super Yang-Millstheorie in vier Dimensionen (N=4 SYM). Es existieren viele Indizien dafür, dass die Theorie exakte Lösungen zulässt. Dies lässt sich zurückführen auf die Integrabilität der Theorie, eine unendlich dimensionale Symmetriealgebra, die die Theorie stark einschränkt. Neben besagter Integrabilität besitzt diese Theorie auch andere spezielle Eigenschaften. So ist sie des am besten verstandenen Beispiels der Eich-/Gravitations Dualität durch die AdS/CFT Korrespondenz. Ausserdem sind die Streuamplituden von Gluonen auf Baumgraphenniveau in N=4 SYM die selben wie in Quantenchromodynamik. Diese Streuamplituden besitzen eine elegante Struktur und stellen sich als deutlich simpler heraus, als die dazugehörigen Feynmangraphen vermuten lassen. Tatsächlich umgehen viele der zur Berechnung von Streuamplituden entwickelten Masseschalenmethoden die Feynmangraphen, indem sie vorrübergehend manifeste Unitarität und Lokalität aufgeben und dadurch die Rechnungen stark vereinfachen. Alle diese Entwicklungen suggerieren, dass der konventionelle Formalismus der Theorie mit Hilfe der Wirkung im Minkowskiraum nicht der aufschlussreichste oder effizienteste Weg ist, die Theorie zu untersuchen. Diese Arbeit untersucht der Hypothese, ob dass stattdessen Twistorvariablen besser geeignet sind, die Theorie zu beschreiben. Der Twistorformalismus wurde zuerst von Roger Penrose eingeführt. Auf dem klassischen Level ist die holomorphe Chern-Simonstheorie im Twistorraum äquivalent zur klassischen selbst-dualen Yang-Mills Lösung in der Raumzeit. Die volle Twistorwirkung, welche eine Störung um diesen klassisch integrablen Sektor ist und durch eine Eichbedingung auf die N=4 SYM Wirkung reduziert werden kann, produziert unter einer anderen Eichbedingung alle sogenannten maximalhelizitätsverletzenden
(MHV) Amplituden auf Baumgraphenniveau. Durch die Einführung eines Twistorpropagators konnten auch NkMHV Amplituden effizient beschrieben werden. In dieser Arbeit erweitern wir den Twistorformalismus um auch Größen, die sich nicht auf den Masseschalen befinden, beschreiben zu können. Wir untersuchen alle lokalen eichinvarianten zusammengesetzten Operatoren im Twistorraum und zeigen, dass sie alle Baumgraphenniveau-Formfaktoren des sogenannten MHV-Typs erzeugen. Wir erweitern diese Methode zu NMHV und öher NkMHW Level in Anlehnung an die Amplituden. Schliess lich knüpfen wir an die Integrabilität an, indem wir den ein-Schleifen Dilatationsoperator in dem skalaren Sektor der Theorie im Twistorraum berechnen.The Standard Model of particle physics has proven to be, with the exception of general relativity, the most accurate description of nature to this day. Perturbative calculations for certain quantities in Quantum Chromo Dynamics (QCD) have led to the highest precision predictions that have been experimentally verified. However, for certain sectors and energy regimes, perturbation theory breaks down and one must look for alternative methods. Much can be learned from studying a close cousin of the standard model, called planar N = 4 super Yang-Mills theory in four dimensions (N = 4 SYM), for which a lot of evidence exists that it admits exact solutions. This exact solvability is due to its quantum integrability, a hidden infinite symmetry algebra that greatly constrains the theory, which has led to a lot of progress in solving the spectral problem. Integrability aside, this non-Abelian quantum field theory is special in yet other ways. For example, it is the most well understood example of a gauge/gravity duality via the AdS/CFT correspondence. Furthermore, at tree level the scattering amplitudes in its gluon sector coincide with those of Quantum Chromo Dynamics. These scattering amplitudes exhibit a very elegant structure and are much simpler than the corresponding Feynman diagram calculation would suggest. Indeed, many on-shell methods that have been developed for computing these scattering amplitudes circumvent the tedious Feynman calculation, by giving up manifest unitarity and locality at intermediate stages of the calculation, greatly simplifying the work. All these developments suggest that the conventional way in which the theory is presented, i.e. in terms of the well- known action on Minkowski space, might not be the most revealing or in any case not the most efficient way. This thesis investigates whether instead twistor variables provide a more suitable description. The twistor formalism was first introduced by Roger Penrose. At the classical level, a holomorphic Chern-Simons theory on twistor space is equivalent to classically integrable self-dual Yang-Mills solutions in space-time. A quantum perturbation around this classically integrable sector reduces to the conventional N = 4 SYM action by imposing a partial gauge condition. This action generates all so-called maximally helicity violating (MHV) amplitudes at tree level directly, when a different gauge was chosen. By including a twistor propagator into the formalism, also higher degree NkMHV amplitudes can be described efficiently. In this thesis we extend this twistor formalism to encompass (partially) off-shell quantities. We describe all gauge-invariant local composite operators in twistor space and show that they immediately generate all tree-level form factors of the MHV type. We use the formalism to compute form factors at NMHV and higher NkMHV level in parallel to how this was done for amplitudes. Finally, we move on to integrability by computing the one-loop dilatation operator in the scalar sector of the theory in twistor space.
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Weil, Esther [Verfasser]. "Meson transition form factors and electromagnetic decays in the Dyson-Schwinger-approach / Esther Danielle Weil". Gießen : Universitätsbibliothek, 2020. http://d-nb.info/1210444658/34.
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Weil, Esther Danielle [Verfasser]. "Meson transition form factors and electromagnetic decays in the Dyson-Schwinger-approach / Esther Danielle Weil". Gießen : Universitätsbibliothek, 2020. http://d-nb.info/1210444658/34.
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Tonguc, Baris Tamer Souder Paul A. "A measurement of parity-violating asymmetry with polarized electrons scattered from protons and implications for strange form factors". Related Electronic Resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2003. http://wwwlib.umi.com/cr/syr/main.
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Oliveira, Orlando Olavo Aragao Aleixo Nerves de. "Mass spectrum and form factors for heavy baryons and a study of stochastic gauge fixing in lattice QCD". Thesis, University of Edinburgh, 1996. http://hdl.handle.net/1842/12727.
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In this thesis we study two aspects of the lattice formulation of Quantum Chromodynamics (QCD). We first describe the study of baryons with one heavy and two light quarks. We compute the full spectrum for the ground state of the channels with quantum numbers JP = 1/2 +, 3/2+, isospin I = 0,1 and strangeness S = 0, -1, -2. For the channel with quantum numbers Jp = 1/2+ we discuss the form factors for semileptonic decays of heavy baryons, compute the Isgur-Wise function and study its dependence on the light quark mass. In the second part of this thesis, we report the numerical results of a first study of a one-parameter family of covariant, non-perturbative gauge-fixing conditions. The gauge dependence of the gluon propagator is discussed.
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Wilhelm, Matthias Oliver. "Form factors and the dilatation operator in N = 4 super Yang-Mills theory and its deformations". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17453.
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Im ersten Teil dieser Dissertation untersuchen wir Formfaktoren von allgemeinen eichinvarianten lokalen zusammengesetzten Operatoren in der N=4 Super-Yang-Mills-Theorie bei verschiedenen Schleifenordnungen und Anzahlen externer Felder. Wir zeigen, wie Masseschalen-Methoden zu ihrer Berechnung genutzt werden können, und extrahieren aus ihnen insbesondere den Dilatationsoperator. Wir untersuchen auch die Eigenschaften der zugehörigen Rückstandsfunktionen. Des Weiteren verallgemeinern wir Masseschalen-Diagramme, Graßmann-Integrale und die integrabilitätsinspirierte Technik der R-Operatoren zur Anwendung auf Formfaktoren, wobei wir uns auf das Beispiel des chiralen Teils des Energie-Impuls-Tensors konzentrieren. Im zweiten Teil untersuchen wir die Beta- und die Gamma-i-Deformation. Bei diesen handelt es sich um die allgemeinste supersymmetrische beziehungsweise nicht-supersymmetrische feldtheoretische Deformation von N=4 Super-Yang-Mills-Theorie, welche auf der Ebene des asymptotischen Bethe-Ansatzes integrabel sind. Hierbei tritt ein neuer Effekt der endlichen Systemgröße auf, der durch Doppelspurstrukturen in der deformierten Lagrange-Dichte hervorgerufen wird und den wir Vorwickeln nennen. Während die Beta-Deformation für sich an ihren nicht-verschwindenden IR-Fixpunkten befindliche Doppelspurkopplungen konform invariant ist, weist die Gamma-i-Deformation rennende Doppelspurkopplungen ohne Fixpunkte auf, was die konforme Invarianz selbst im planaren Limes bricht. Nichtsdestotrotz erlaubt die Gamma-i-Deformation hochgradig nicht-triviale Tests der Integrabilität bei beliebig hohen Schleifenordnungen.In the first part of this thesis, we study form factors of general gauge-invariant local composite operators in N=4 super Yang-Mills theory at various loop orders and for various numbers of external legs. We show how to use on-shell methods for their calculation and in particular extract the dilatation operator from the result. We also investigate the properties of the corresponding remainder functions. Moreover, we extend on-shell diagrams, a Graßmannian integral formulation and an integrability-based construction via R-operators to form factors, focussing on the chiral part of the stress-tensor supermultiplet as an example. In the second part, we study the beta- and the gamma-i-deformation, which were respectively shown to be the most general supersymmetric and non-supersymmetric field-theory deformations of N=4 super Yang-Mills theory that are integrable at the level of the asymptotic Bethe ansatz. For these theories, a new kind of finite-size effect occurs, which we call prewrapping and which emerges from double-trace structures that are required in the deformed Lagrangians. While the beta-deformation is conformal when the double-trace couplings are at their non-trivial IR fixed points, the gamma-i-deformation has running double-trace couplings without fixed points, which break conformal invariance even in the planar theory. Nevertheless, the gamma-i-deformation allows for highly non-trivial field-theoretic tests of integrability at arbitrarily high loop orders.
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Zimmermann, Iris [Verfasser]. "Feasibility studies for the measurement of the time-like electromagnetic proton form factors at the PANDA experiment / Iris Zimmermann". Mainz : Universitätsbibliothek Mainz, 2018. http://d-nb.info/1170178448/34.
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Tijaja, Julia Puspadewi. "Exogeneous factors and domestic agency in value chain dynamics : Lessons form the Thai Cassava value chains". Thesis, Open University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530491.
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Masetti, Lucia [Verfasser]. "Measurement of the Ke4 form factors and of the pi-pi scattering length alpha00 / Lucia Masetti". Aachen : Shaker, 2007. http://d-nb.info/1170527108/34.
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Cromer, Bob E. "An analysis of the critical factors affecting the continued development of fiber as an art form". Virtual Press, 1987. http://liblink.bsu.edu/uhtbin/catkey/520473.
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The purpose of the study was to examine the status of contemporary fiber as an art form and to identify critical factors affecting its continued development.An extensive search of available literature was conducted. From this search, coupled with the researcher's extensive personal involvement with fiber, populations were identified and questionnaires were designed.Three pertinent but different populations, consisting of fiber artists, college/university and art school heads, and museum, gallery, and textile directors/curators were selected to receive the questionnaires. The questionnaires were designed to reflect the similarities and differences of the population.Data were treated to comparative percentages, valid percentages, cumulative percentages, frequencies, and Chi-Squares. Four major concerns were identified and discussed. They are:1. Fiber as Fine Art2. The Importance of Content and Message Orientation in Fiber3. The Problem of Plurality and Fiber4. The Need for a Critical Language Relative to FiberFindings and Conclusions1. The division between fine art and crafts still exists. Therefore, the division also exists for fiber art, which is part of the crafts discipline.2. Most individuals are not in favor of limiting the parameters of what constitutes fiber art in order to help gain a clearer understanding of what fiber art really is.3. There does not appear to be a critical language for fiber art except that which is technique, method, or materials based.4. The opinion of whether fiber art should be message or statement oriented is divided. Some were in agreement while others were not. In addition, some of the respondents answered with "sometimes."