Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A física de partículas vem atualmente estudando tópicos como o plasma de quarks e glúons (QGP), o bóson de Higgs e a matéria escura, que requerem experimentos de colisões entre partículas cada vez mais energéticas. Para isso, são necessários aceleradores capazes de gerar partículas projéteis a cada vez mais altas energias, o que pode levar a uma nova física. Quando novos dados surgem nos laboratórios, novos processos são necessários para explicar estes dados e algumas vezes a estrutura interna das partículas envolvidas é desconhecida. Nos modelos teóricos, usados para descrever estes processos de espalhamento, é comum introduzir o fator de forma. O fator de forma é simplesmente uma maneira de simular a sub-estrutura das partículas envolvidas nestes processos com função da energia ou momento. A obtenção dos atores de forma pode ser feita usando o método conhecido como Regras de Soma da QCD (RSQCD). Neste trabalho, será estudado o vértice D*Dp usando as RSQCD, de modo que seja possível obter os seus fatores de forma e sua constante de acoplamento. Para isso, foram estudados os casos em que o méson ρ e o méson D estão fora de suas camadas de massa. O vértice D*Dp é muito importante para entender melhor o ρπ Puzzle, onde o méson Ј/ψ decai ρπ em com um branching ratio maior do que o esperado (este é um processo suprimido pela regra de OZI). Estudando este processo com graus de liberdade mesnicos, é possível escapar da regra de OZI, uma vez que o processo Ј/ψ→ DD → ρπ não é suprimido por OZI. Ao se fazer isso, aparecerá, entre outros, o vértice D*Dp . Este é um vértice que também aparece em outros decaimentos, como por exemplo X(3872) →Ј/ψp e B→Ј/ψD. Ao final do desenvolvimento, os resultados obtidos neste trabalho para o vértice D*Dp foram comparados com outros encontrados na literatura, se mostrando compatíveis com estes outros trabalhos. / The particle physics have been studying topics like the Quark-Gluon Plasma (QGP), Higgs boson and dark matter, which require experiments in heavy-ion collisions. Therefore, accelerators capable of generate high energy particle beams are necessary and may generate new physics. When new data arise in the laboratories, new processes are necessary to explain this data and sometimes, the internal structure of the involved particles is unknow or are virtual. In the theoretical models, used to describe this scattering processes, is common to introduce the form factors. The form factor is a way to simulate the sub-structure of the involved particles as function of energy or momentum. The form factor can be obtained using a method called QCD Sum Rules (QCDSR). In this work, the vertex D*Dp will be studied using the QCDSR, in order to obtain its form factors and coupling constant.The D*Dp vertex is very important to understand the ρπ Puzzle, where the Ј/ψ meson decays in ρπ with a branching ratio bigger than expected (this is a suppressed process by the OZI Rule). Studying this process with hadronic degrees of freedom, its possible to escape of the OZI rule, once the Ј/ψ→ DD → ρπ is not suppressed by the OZI rule. In this process, the D*Dp vertex is necessary. There are other processes where this vertex is necessary: X(3872)→Ј/ψp and B→Ј/ψD for example. In this work, was only possible to obtain results from the ρ off-shell diagram. This results were compared with others obtained in the literature.

Nesta tese de doutorado é utilizado o método das Regras de Soma da QCD para estudar a natureza dos novos estados ressonantes do charmonium: Y(3930), Y(4140), X(4350), Y(4260), Y(4360) e Y(4660). Há fortes evidências de que estes estados possuam estruturas hadrônicas não convencionais (ou exóticas) uma vez que as suas respectivas massas e canais de decaimento observados experimentalmente são inconsistentes com o que é esperado para o estado ressonante convencional do charmonium, J/psi. O mesmo fenômeno ocorre no setor do bottomonium, onde os novos estados Yb(10890) e Yb(11020) observados recentemente poderiam indicar a existência de novos estados exóticos do bottomonium. Neste sentido, verifica-se que o estado Y(4140) poderia ser descrito ou por uma estrutura molecular Ds*Ds* (0++) ou mesmo uma mistura entre estados moleculares Ds*Ds* (0++) e D*D* (0++). Já os estados Y(3930) e o X(4350) não podem ser descritos por correntes moleculares D*D* (0++) e Ds*Ds* (1-+), respectivamente. Verifica-se também que a estrutura molecular Psi(2S) f_0(980) (1--) descreve muito bem a massa do estado Y(4660). Uma extensão ao setor do bottomonium indica que o estado molecular Y(2S) f_0(980) é um bom candidato para descrever a estrutura do estado Yb(10890). É feita também uma estimativa para os possíveis estados moleculares formados por mésons D(*) e B(*), que poderão ser observados em futuros experimentos realizados pelo LHC. Um amplo estudo, utilizando o formalismo das Regras de Soma e também da Dupla Razão das Regras de Soma, é feito para calcular as massas dos bárions pesados na QCD. As estimativas para as massas dos bárions com um (Qqq) e com dois (QQq) quarks pesados são um excelente teste para a capacidade do método das regras de soma em prever a massa dos bárions que ainda não foram observados. / In this thesis, the QCD sum rules approach was used to study the nature of the new charmonium resonances: Y(3930), Y(4140), X(4350), Y(4260), Y(4360) and Y(4660). There is a strong evidence that these states have non-conventional (or exotic) hadronic structures since their respective masses and decay channels observed experimentally are inconsistent with what expected for a conventional charmonium state, J/psi. The same phenomenon occurs on the bottomonium sector, where new states like Yb(10890) and Yb(11020) observed recently could indicate the existence of new bottomonium exotic states. In this way, one verifies that the state Y(4140) could be described as a Ds*Ds* (0++) molecular state or even as a mixture of Ds*Ds* (0++) and D*D* (0++) molecular states. For the Y(3930) and X(4350) states, both cannot be described as a D*D* (0++) and Ds*Ds* (1-+), respectively. From a sum rule point of view, the Y(4660) state could be described as a Psi(2s) f_0(980) (1--) molecular state. The extension to the bottomonium sector is done in a straightforward way to demonstrate that the Y(2S) f_0(980) molecular state is a good candidate for describing the structure of the Yb(10890) state. In the following, one estimates the mass of the exotic Bc-like molecular states using QCD Sum Rules - these exotic states would correspond to bound states of D(*) and B(*) mesons. All of these mass predictions could (or not) be checked in a near future experiments at LHC. A large study using the Double Ratio of Sum Rules approach has been evaluated for the study of the heavy baryon masses in QCD. The obtained results for the unobserved heavy baryons, with one (Qqq) and two (QQq) heavy quarks will be an excellent test for the capability of the sum rule approach in predicting their masses.

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No. of bitstreams: 1 Dissertação - Maria Oneide Silva de Moraes.pdf: 9993702 bytes, checksum: d0ede70d56d052b19d6265bf315f6128 (MD5) Previous issue date: 2013-03-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The absolute values of the photoabsorption cross section of compounds are of great importance in the fields of physics, chemistry, biology, therapy and related fields. Studies of natural products are also of great importance several areas of science and innovation, however, information related to the values of the photoabsorption cross section in the vacuum ultraviolet region are scarce in the literature. In this paper a study of the electronic excitations of the molecule isoprene using a spectrometer energy loss of electrons from low-resolution (0,8– 1,0 eV FWHM) at the Laboratory for Photon and Electron Impact (LIFE-UFRJ). The energy loss spectra of electrons were obtained in the range 3-100 eV at various angles of scattering with incident energy of 1 keV. The spectra of generalized oscillator strength (GOS) for the isoprene molecule were obtained by the Bethe-Born conversion. The spectrum GOS obtained in the angle of impact 2o was extrapolated to the strength oscillator photoabsorption optical using the universal formula Msezane and Sakmar (1997). The photoabsorption cross sections on an absolute scale were determined by of the static polarizability of isoprene applying the sum rule S(-2) in the photoabsorption spectrum. The contributions of the inner layer photoabsorption above 100 eV were estimated from a fit polynomial curve. Other sum rules were used to estimate the values of physical properties isoprene as sum rule S(0) is equal to the number of electrons on the target (36,45 a. u.), the rule logarithmic L(0) is the stopping power of the molecule (18,05 a.u.), the rule logarithmic L(1) is related to the effect straggling referring to fluctuations of the incident beam (22,49 a.u.) and rule logarithmic L(2) for the Lamb shift (55,27 a.u.). The set of spectra GOS obtained at different scattering angles were presented in Bethe surface to isoprene. Two regions stand out: a region dominated by the optical selection rules for electronic transitions of the absorption, and the other region, we observed a strong angular dependence on the momentum of the incident electrons becomes significant.The Bethe surface and the sum rules are unpublished experimental data in the literature. The absolute values of the cross section and the Bethe surface can contribute to a complete understanding of the electronic excitations of the molecule isoprene induced by collisions of charged particles. It is expected that these absolute valuesmay be useful as references to theoretical calculations and experimental in the electronic spectra of isoprene. / Os dados de seção de choque de fotoabsorção de compostos são de grande importância nas áreas de física, química, biologia, terapia e áreas afins. Os estudos de produtos naturais também são de grande importância em diversas áreas científicas e de inovação, porém, informações relacionadasaos valores de seção de choque de fotoabsorção na região ultravioleta de vácuo são incipientes na literatura. Neste trabalho foi feito um estudo das excitações eletrônicas da molécula isopreno utilizando um espectrômetro de perda de energia de elétrons de baixa resolução (0,8 – 1,0 eV FWHM) no Laboratório de Impacto de Fótons e Elétrons (LIFE-UFRJ). Os espectros de perda de energia de elétrons foram obtidos na faixa de 3 a 100 eV em vários ângulos de espalhamentos com energia incidente de 1 keV. Os espectros de força do oscilador generalizado (FOG) para a molécula isopreno foram obtidos pela conversão de Bethe-Born. O espectro de FOG obtido no ângulo de impacto de 2o foi extrapolado para força do oscilador de fotoabsorção ótico utilizando a fórmula universal de Msezane e Sakmar (1997). As seções de choque de fotoabsorção em escala absoluta foram determinadas por meio da polarizabilidade estática do isopreno aplicando a regra de soma S(-2) no espectro de fotoabsorção. As contribuições da fotoabsorção da camada interna acima de 100 eV foram estimadas com o ajuste de uma curva polinomial.Outras regras de somas foram utilizadas para estimar os valores de propriedades físicas para o isopreno como a regra de soma S(0) que é igual ao número de elétrons no alvo (36,45 u. a., unidades atômicas), a regra de soma logarítmica L(0) é o stopping power da molécula (18,05 u. a.), a regra de soma logarítmica L(1) é o efeito straggling referente às flutuações estáticas do feixe incidente (22,49 u. a.) e a regra de soma logarítmica L(2) referente ao deslocamento de Lamb (55,27 u. a.). O conjunto de espectros de FOG obtidos em diferentes ângulos de espalhamento foi apresentado na Superfície de Bethe para o isopreno. Duas regiões se destacaram: uma região dominada pelas regras de seleção ópticas de transições eletrônicas dos processos de absorção, e a outra região, foi observado uma forte dependência angular em que o momento linear dos elétrons incidentes torna-se significativo. A Superfície de Bethe e as regras de somas são resultados experimentais inéditos na literatura. Os valores absolutos de seção de choque e a Superfície de Bethe podem contribuir para um entendimento completo das excitações eletrônicas da molécula isopreno induzidas por colisões de partículas carregadas. É esperado que estes valores absolutos possam ser úteis como referências em cálculos teóricos e experimentais para o espectro eletrônico do isopreno.

Efficient design of high-voltage power cables is important to achieve an economical delivery of electric power from wind farms and power plants over the very long distances as well as the overseas electric power. The main focus of this thesis is the investigation of electromagnetic losses in components of high-voltage power cables. The objective of the ongoing research is to develop the theory and optimization techniques as tools to make material choices and geometry designs to minimize the high-frequency attenuation and dispersion for HVDC power cables and the power losses associated with HVAC cables. Physical limitations, dispersion relationships and the application of sum rules as well as convex optimization will be investigated to obtain adequate physical insight and a priori modeling information for these problems. For HVAC power cables, the objectives are addressed by performing measurements and estimation of complex valued permeability of cable armour steel in Papers I and II. Efficient analytical solutions for the electromagnetic field generated by helical structures with applications for HVAC power cables have been obtained in Paper III. For HVDC power cables, estimation of insulation characteristics from dielectric spectroscopy data using Herglotz functions, convex optimization and B-splines, has been investigated in Papers V and VI. The unique solution requirements in waveguide problems have been reviewed in Paper IV.

Cette thèse a utilisé la méthode des règles de somme de QCD pour étudier la nature des résonances du charmonium suivantes: Y(3930), Y(4140), X(4350), Y(4260), Y(4360) et Y(4660). Il y a des fortes indications que ces états ont des structures hadroniques non conventionnelles (ou exotiques) lorsque leurs masses respectives et les modes de désintégration observés expérimentalement sont incompatibles avec ce qui est attendu pour l'état conventionnel du charmonium.Le même phénomène se produit dans le secteur du bottomonium, où les nouveaux états Yb(10890) et Yb(11020), observeés récemment pourraient indiquer l'existence de nouveaux états exotiques du bottomonium. De cette façon, on vérifie que l'état Y(4140) peut être décrit soit par une structure moléculaire D*s D*s (0++) ou par une mélange entre les états moléculaires D*s D*s (0++) et D*D* (0++). Les états Y(3930) et X(4350) ne peuvent pas être décrites par les courants moléculaires D*D* (0++) et D*s D*so (1-+), respectivement. On vérifie également que la structure moléculaire psi' f0(980) (1--) réproduit très bien la masse de l'état Y(4660). Une extension naturelle au secteur du bottomonium indique que l'état moléculaire Y' f0(980) est un bon candidat pour l'état Yb(10890). On a également fait une estimation pour les états moléculaires possibles formées par des mésons D et B, ce qui pourra être observé dans des expériences futures au LHC.Une vaste étude, en utilisant le formalisme habituel des règles de somme et aussi le Double Rapport des règles de somme, est fait pour calculer les masses des baryons lourds en QCD. Les estimations pour les masses des baryons avec un (Qqq) et deux (QQq) quarks lourds sont un excellent test pour la capacité de la méthode de règles de somme à prédire les masses des baryons qui n'ont pas encore été observés. / The QCD sum rules approach was used to study the nature of the following charmonium resonances: Y(3930), Y(4140), X(4350), Y(4260), Y(4360) and Y(4660). There is strong evidence that these states have a non-conventional (or exotic) hadronic structures since their respective masses and decay channels observed experimentally are inconsistent with expected for a conventional charmonium state. The same phenomenon occurs on the bottomonium sector, where new states like Yb(10890) and Yb(11020) observed recently could indicate the existence of new bottomonium exotic states. In this way, one verifies that the state Y(4140) could be described as a D*s D*s (0++) molecular state or even as a mixture of D*s D*s (0++) and D*D* (0++) molecular states. For the Y(3930) and X(4350) states, both cannot be described as a D*D* (0++) and D*s D*s0 (1−+), respectively. From the sum rule point of view, the Y(4660) state could be described as a ψ' f0(980) (1−−) molecular state. The extension to the bottomonium sector is done in a straightforward way to demonstrate that the Y' f0(980) molecular state is a good candidate for describing the structure of the Yb(10890) state. In the following, one estimates the mass of the exotic Bc-like molecular states using QCD sum rules - these exotic states would correspond to a bound states of D(*) and B(*) mesons. All of these mass predictions could (or not) be checked in a near future experiments at LHC.A large study using the Double Ratio of sum rules approach has been evaluated for the study of the heavy baryon masses in QCD. The obtained results for the baryons with one (Qqq) and two (QQq) heavy quarks will be an excellent test for the capability of the sum rule approach in predicting mass of the baryons which have not yet been observed.

The modifications of hadronic properties caused by an ambient nuclear medium are investigated within the scope of QCD sum rules. This is exemplified for the cases of the omega meson, the nucleon and the D meson. By virtue of the sum rules, integrated spectral densities of these hadrons are linked to properties of the QCD ground state, quantified in condensates. For the cases of the omega meson and the nucleon it is discussed how the sum rules allow a restriction of the parameter range of poorly known four-quark condensates by a comparison of experimental and theoretical knowledge. The catalog of independent four-quark condensates is covered and relations among these condensates are revealed. The behavior of four-quark condensates under the chiral symmetry group and the relation to order parameters of spontaneous chiral symmetry breaking are outlined. In this respect, also the QCD condensates appearing in differences of sum rules of chiral partners are investigated. Finally, the effects of an ambient nuclear medium on the D meson are discussed and relevant condensates are identified. / Die Veränderungen von Hadroneneigenschaften durch ein umgebendes nukleares Medium (Kernmaterie) werden mit der Methode der QCD-Summenregeln untersucht. Dies wird am Beispiel des omega-Mesons, des Nukleons und des D-Mesons vorgeführt. Durch die Summenregeln werden integrierte Spektraldichten dieser Hadronen in Beziehung zu Eigenschaften des QCD-Grundzustandes, quantifiziert in Kondensaten, gesetzt. Diskutiert wird am Beispiel des omega-Mesons und des Nukleons, wie diese Summenregeln eine Einschränkung des Parameterbereiches von wenig bekannten Vierquark-Kondensaten durch Vergleich von experimentellen und theoretischen Erkenntnissen erlauben. Ein Katalog unabhängiger Vierquark-Kondensate wird aufgestellt und Relationen zwischen diesen Kondensaten werden deutlich gemacht. Das Verhalten der Vierquark-Kondensate unter der chiralen Symmetriegruppe und der Zusammenhang mit Ordnungsparametern spontaner chiraler Symmetriebrechung werden behandelt. In dieser Hinsicht werden auch die in Differenzen der Summenregeln chiraler Partner eingehenden QCD-Kondensate untersucht. Schließlich werden die Effekte endlicher Kerndichten beim D-Meson diskutiert und relevante Kondensate identifiziert.

Das Zusammenspiel von Hadronen und Modifikationen ihrer Eigenschaften auf der einen Seite und spontaner chiraler Symmetriebrechung und Restauration auf der anderen Seite wird untersucht. Es werden die QCD Summenregeln für D und B Mesonen in kalter Materie berechnet. Wir bestimmen die Massenaufspaltung von D - D-bar und B - B-bar Mesonen als Funktion der Kerndichte und untersuchen den Einfluss verschiedener Kondensate in der Näherung linearer Dichteabhängigkeit. Die Analyse beinhaltet ebenfalls D_s und D^*_0 Mesonen. Es werden QCD Summenregeln für chirale Partner mit offenem Charmfreiheitsgrad bei nichtverschwindenden Nettobaryonendichten und Temperaturen vorgestellt. Es wird die Differenz sowohl von pseudoskalaren und skalaren Mesonen, als auch von Axialvektor- und Vektormesonen betrachtet und die entsprechenden Weinberg-Summenregeln hergeleitet. Basierend auf QCD Summenregeln werden die Auswirkungen eines Szenarios auf das rho Meson untersucht, in dem alle chiral ungeraden Kondensate verschwinden wohingegen die chiral symmetrischen Kondensate ihren Vakuumwert behalten. Die komplementären Folgerungen einer Massenverschiebung und Verbreiterung der rho Mesonanregung werden diskutiert. Ein alternativer Zugang basierend auf gekoppelten Dyson-Schwinger- und Bethe-Salpeter-Gleichungen für Quarkbindungszustände wird untersucht. Zu diesem Zwecke wird die analytische Struktur des Quarkpropagators in der komplexen Ebene numerisch untersucht und die Möglichkeit getestet die Anwendbarkeit auf den Sektor der schwer-leicht Quark Systeme im skalaren und pseudoskalaren Kanal, wie dem D Meson, durch Variation des Impulsteilungsparameters zu erweitern. Die Lösungen der Dyson-Schwinger-Gleichung in der Wigner-Weyl-Phase der chiralen Symmetrie bei nichtverschwindenden Stromquarkmassen wird benutzt um den Fall einer expliziten Symmetriebrechung ohne spontane Symmetriebrechung zu untersuchen. / The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D - D-bar and B - B-bar mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D_s and $D^*_0 mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the rho meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Das Zusammenspiel von Hadronen und Modifikationen ihrer Eigenschaften auf der einen Seite und spontaner chiraler Symmetriebrechung und Restauration auf der anderen Seite wird untersucht. Es werden die QCD Summenregeln für D und B Mesonen in kalter Materie berechnet. Wir bestimmen die Massenaufspaltung von D - D-bar und B - B-bar Mesonen als Funktion der Kerndichte und untersuchen den Einfluss verschiedener Kondensate in der Näherung linearer Dichteabhängigkeit. Die Analyse beinhaltet ebenfalls D_s und D^*_0 Mesonen. Es werden QCD Summenregeln für chirale Partner mit offenem Charmfreiheitsgrad bei nichtverschwindenden Nettobaryonendichten und Temperaturen vorgestellt. Es wird die Differenz sowohl von pseudoskalaren und skalaren Mesonen, als auch von Axialvektor- und Vektormesonen betrachtet und die entsprechenden Weinberg-Summenregeln hergeleitet. Basierend auf QCD Summenregeln werden die Auswirkungen eines Szenarios auf das rho Meson untersucht, in dem alle chiral ungeraden Kondensate verschwinden wohingegen die chiral symmetrischen Kondensate ihren Vakuumwert behalten. Die komplementären Folgerungen einer Massenverschiebung und Verbreiterung der rho Mesonanregung werden diskutiert. Ein alternativer Zugang basierend auf gekoppelten Dyson-Schwinger- und Bethe-Salpeter-Gleichungen für Quarkbindungszustände wird untersucht. Zu diesem Zwecke wird die analytische Struktur des Quarkpropagators in der komplexen Ebene numerisch untersucht und die Möglichkeit getestet die Anwendbarkeit auf den Sektor der schwer-leicht Quark Systeme im skalaren und pseudoskalaren Kanal, wie dem D Meson, durch Variation des Impulsteilungsparameters zu erweitern. Die Lösungen der Dyson-Schwinger-Gleichung in der Wigner-Weyl-Phase der chiralen Symmetrie bei nichtverschwindenden Stromquarkmassen wird benutzt um den Fall einer expliziten Symmetriebrechung ohne spontane Symmetriebrechung zu untersuchen. / The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D - D-bar and B - B-bar mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D_s and $D^*_0 mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the rho meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Die vorliegende Arbeit beschreibt die Messung der polarisierten Strukturfunktion g1p des Protons in der polarisationsabh"angigen tief inelastischen Positron-Proton-Streuung bei einer Schwerpunktenergie von 7.5 GeV. Die Analyse umfasst die 1997 mit dem Hermes-Experiment am Hera-Positronring aufgezeichneten Daten der Streuung polarisierter Positronen der Energie 27.6 GeV an einem polarisierten Wasserstofftarget. Aus den Z"ahlraten der inklusiv nachgewiesenen, selektierten Positronen f"ur die parallele und die antiparallele Ausrichtung der Spinvektoren von Strahlteilchen und Targetatomen wurde die Streuquerschnitts- Asymmetrie der Positron-Proton-Streuung bestimmt. In verschiedenen Korrekturverfahren wurden Untergrundprozesse, Spektrometereinfl"usse sowie Strahlungskorrekturen ber"ucksichtigt. Die Untergrundkorrekturen wurden aus den Daten, die Spektrometerkorrekturen aus einer Monte-Carlo- Simulation ermittelt. Die Abh"angigkeit der Monte-Carlo- und Strahlungskorrekturen von der gew"ahlten Modell-Asymmetrie zur Beschreibung der polarisationsabh"angigen Effekte wurde durch die Anwendung eines iterativen Verfahrens minimiert. Aus der vollst"andig korrigierten Streuquerschnitts-Asymmetrie wurde die Asymmetrie g1/F1 im kinematischen Bereich 0.021 < x < 0.85 und Q2 > 0.8 GeV^2 mit einer systematischen Unsicherheit von etwa 8% bei einer statistischen Genauigkeit von 6% bis 20%, ansteigend f"ur abnehmende x-Werte, bestimmt. Die aus g1/F1 berechnete polarisierte Strukturfunktion g1p(x,Q2) wird, unter der Annahme einer von q2 unabh"angigen Asymmetry g1/F1, zu einem festen Wert Q2_0 entwickelt. Ihr erstes Moment im gemessenen x-Bereich betr"agt int_{0.021}^{0.85} dx g1p(x,Q2_0) = 0.122 =- 0.003 (stat) =- 0.010 (sys) at Q2_0 = 2.5 GeV^2. Der Vergleich mit den Werten des SMC-Experimentes am CERN und des E143-Experimentes am SLAC f"ur das erste Moment von g1p wurde unter Anwendung des gleichen Integrationsschemas f"ur den jeweils gemeinsam gemessenen x-Bereich sowie f"ur gleiche Q2_0 Werte durchgef"uhrt. Das Ergebnis der vorliegenden Analyse befindet sich, bezogen auf die statistische Genauigkeit der Messungen, in "Ubereinstimmung innerhalb von 0.6 bzw. 1.2 Standardabweichungen mit den Resultaten des E143- bzw. SMC-Experimentes. Durch Extrapolation der Strukturfunktion auf den gesamten x-Bereich [0,1] wird das erste Moment zu \int_{0}^{1} dx g1p(x,Q2_0) = 0.132 +- 0.003 (stat) +- 0.010 (sys) +- 0.006 (extr) bestimmt, wobei der zus"atzliche Fehler die Unsicherheit in der Extrapolation x -> 0 wiedergibt. Die Interpretation der vorliegenden Messung im Rahmen des Quark-Parton-Modells unter Ber"ucksichtigung von QCD-Korrekturen der Ordnung O(alphaS^3) ergibt einen Beitrag der Quarks zum Gesamtspin des Nukleons von (30 +- 10)% f"ur Q2_0 = 2.5 GeV^2. Dieses Ergebnis entspricht einer Abweichung von der Ellis-Jaffe-Vorhersage um 2.5 Standardabweichungen, bezogen auf den angegebenen Gesamtfehler, und f"uhrt im Kontext des Quark-Parton-Modells zur Interpretation negativ polarisierter Strange-Seequarks mit einem Beitrag von (-9 +- 4)% f"ur Q2_0 = 2.5 GeV^2. Von verschiedenen Gruppen werden aus QCD-Analysen unterschiedlicher Datens"atze Beitr"age der Quarks zum Nukleonspin von 19% bis 44% angegeben. Unter Hinzunahme der Hermes-Messung der polarisierten Neutronstrukturfunktion g1n wurde der Wert der fundamentalen Bjorken-Summenregel f"ur Q2_0 = 2.5 GeV^2 bestimmt. Dieser Wert befindet sich, bei einer auf den Gesamtfehler bezogenen Genauigkeit von 13%, innerhalb von 0.5 Standardabweichungen in "Ubereinstimmung mit der theoretischen Vorhersage, berechnet unter Ber"ucksichtigung von QCD-Korrekturen der Ordnung O(\alphaS^3). / The subject of this thesis is the measurement of the polarised structure function g1p of the proton in deeply inelastic positron-proton-scattering at a centre of mass energy of 7.5 GeV. The data used in the analysis were recorded during the 1997 running period of the Hermes experiment using a longitudinally nuclear polarised hydrogen target in the 27.6 GeV Hera polarised positron storage ring. The cross section asymmetry of positron-proton-scattering has been measured by counting the number of inclusively reconstructed and selected positrons with target spin vector parallel or antiparallel to the beam spin direction. Background processes, spectrometer effects, and radiative corrections have been taken into account by applying different correction procedures. Here background corrections were determined from data while spectrometer corrections were computed from Monte Carlo simulation. The dependence of Monte Carlo and radiative corrections on the model asymmetry chosen to describe polarisation dependent effects has been minimised by applying an iterative procedure. From the fully corrected cross section asymmetry the asymmetry g1/F1 has been computed in the kinematic region 0.021 < x < 0.85 and Q2 > 0.8 GeV^2 with a systematic uncertainty of 8% and a statistical accuracy of 6% to 20%, raising for decreasing x values. The polarised structure function g1p(x,Q2), determined from the asymmetry g1/F1 , was evoluted to a common Q2_0 value assuming g1/F1 to be independent of Q2. Its first moment evaluated in the measured x region is int_{0.021}^{0.85} dx g1p(x,Q2_0) = 0.122 =- 0.003 (stat) =- 0.010 (sys) at Q2_0 = 2.5 GeV^2. This result has been compared with those from E143 at SLAC and from SMC at CERN, both calculated with the same integration scheme and for the kinematic range of Hermes. With respect to the statistical uncertainties the agreement is better than 0.6 and 1.2 standard deviations, respectively. Extrapolation over the entire x range [0,1] yield for the first moment\int_{0}^{1} dx g1p(x,Q2_0) = 0.132 +- 0.003 (stat) +- 0.010 (sys) +- 0.006 (extr) where the additional error gives the uncertainty in the extrapolation x -> 0. The interpretation of this measurement in the framework of the quark parton model taking QCD corrections of the order O(alphaS^3) into account results in a contribution of the quarks to the total nucleon spin of (30 +- 10)% at Q2_0 = 2.5 GeV^2. This result corresponds to a deviation from the Ellis-Jaffe prediction by 2.5 standard deviation regarding the given total uncertainty. Within the quark parton model the deviation can be interpreted as negative polarisation of the strange sea quarks with a contribution of (-9 +- 4)% at Q2_0 = 2.5 GeV^2. Different groups give contributions of the quarks to the nucleon spin of 19% to 44% which were obtained from QCD analyses of various data sets. The fundamental Bjorken sum rule has been determined at Q2_0 = 2.5 GeV^2 using the Hermes measurement of the polarised neutron structure function g1n. With respect to the experimental accuracy of 13 %, the result agrees within 0.5 standard deviation with the theoretical prediction taking QCD corrections of the order O(alphaS^3) into account.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho, foram calculados os fatores de forma e as constantes de acoplamento dos vértices mesônicos J/&#968; DsDs, J/&#968; Ds*Ds e J/&#968; Ds*Ds*usando a técnica das regras de soma da QCD (RSQCD) até a ordem 5 da OPE. Estes três vértices estão envolvidos em algumas das numerosas hipóteses que tentam explicar a estrutura interna de alguns mésons charmosos exóticos que começaram a ser observados a partir de 2003. Tais mésons não se encaixam no espectro do charmonium e/ou apresentam números quânticos exóticos dentro do modelo CQM (constituent quark model). Um exemplo é o méson Y(4140), cujo decaimento observado é no par J/&#968;&#966; enquanto o esperado seria que tivesse decaimento predominante em mésons com open charm, devido à sua massa. Uma das propostas para se entender este méson consiste em estudá-lo como um estado molecular Ds*ar{D}s*, de modo que seu decaimento seria Y(4140) &#8594; Ds* ar{D}s* &#8594; J/&#968;&#966;. Neste processo, aparecerão os vértices de interação estudados neste trabalho, de maneira que o conhecimento mais preciso de seus fatores de forma e de suas constantes de acoplamento pode beneficiar a compreensão sobre a constituição fundamental do Y(4140) assim como a de outros novos estados como o X(4350), Y(4274) e Y(4660) por exemplo. Foram considerados neste trabalho, todos os casos off-shell possíveis para cada um dos três vértices, obtendo assim dois fatores de forma distintos para o vértice J/&#968; DsDs, três para o vértice J/&#968; Ds*Ds e dois para o vértice J/&#968; Ds* Ds*. Nestes três vértices, os fatores de forma para o caso J/&#968; off-shell foram bem ajustados por curvas monopolares enquanto os casos Ds e Ds* foram ajustados por curvas exponenciais, o que está de acordo com o comportamento encontrado em trabalhos anteriores do grupo. Os cálculos das constantes de acoplamento tiveram como resultados: g_{J/&#968; Ds Ds} = 5.98^{+0.67}_{ -0.58}, g_{J/&#968; D*s Ds} = 4.30_{+0.41}^{-0.35}GeV^{-1} e g_{J/&#968; Ds* Ds*} = 7.47^{+1.04}_{-0.71}, resultados estes que estão compatíveis com os trabalhos anteriores que utilizaram as RSQCD para o cálculo das constantes de acoplamento dos vértices J/&#968; D(*)D(*). / In this work, the form factors and coupling constants of the meson vertices J/&#968; DsDs, J/&#968; Ds*Ds and J/&#968; Ds*Ds* have been calculated with the QCD sum rule (QCDSR) technique up to dimension 5 of the operator product expansion (OPE). These three vertices are involved in some of the numerous hypotheses that attempt to explain the internal structure of some exotic charmed mesons which began to be observed since 2003. Such mesons do not fit in the charmonium spectrum and/or have exotic quantum numbers within the CQM (constituent quark model). An example is the Y(4140) meson, which decays in the pair J/&#968;&#966; while the expected would be a dominant decay in open charm mesons. One of the proposals to understand this meson is to study it as a molecular state Ds*{D}s*, so it would decay as Y(4140)&#8594; Ds* {D}s* &#8594; J/&#968;&#966;.In this process, the vertices studied in this work will appear, so the more accurate knowledge of their form factors and their coupling constants can benefit our understanding of the fundamental constitution of the Y(4140) as well as other new states as the X(4350), Y(4274) and Y (4660) eg. In this study all possible off-shell cases for each of these three vertices were considered, thus obtaining two different form factors for the vertex J/&#968; DsDs, three for the vertex J/&#968; Ds*Ds and two for the vertex J/&#968; Ds* Ds*. In these three vertices, the form factors for the J/&#968; off-shell case were well fitted by monopolar curves, while the Ds and Ds* off-shell cases were well fitted by exponential curves which is in agreement with the behavior found in previous work of the group. The calculations of the coupling constants leaded to the following results: g_{J/&#968; Ds Ds} = 5.98^{+0.67}_{-0.58}, g_{J/&#968; Ds* Ds} = 4.30^{+0.41}_{-0.35}GeV^{-1} and g_{J/&#968; Ds* Ds*} = 7.47^{+1.04}_{-0.71}, these results are compatible with previous QCDSR works for the non strange vertices J/&#968;D(*)D(*).