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1
Potter, Christopher Thomas. "A search for the rare decay B⁰ (arrow tau⁺ tau⁻) at the Babar experiment /." view abstract or download file of text, 2005. http://wwwlib.umi.com/cr/uoregon/fullcit?p3181121.
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Thesis (Ph. D.)--University of Oregon, 2005.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 219-223). Also available for download via the World Wide Web; free to University of Oregon users.
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Irwin, Blake A. "Calculation of the meson decays of vector Πvector + pseudoscalar using Q.C.D." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63992.
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Uzzo, Michael. "Stability of quark-antiquark models of mesons: A study on the validity of the spectator, Dirac, and Salpeter equations." W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539623942.
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Mesons are made of quark-antiquark pairs held together by the strong force. The one channel spectator, Dirac, and Salpeter equations can each be used to model this pairing. We look at cases where the relativistic kernel of these equations corresponds to a linear combination of scalar exchange and vector exchange. The vector exchange will be either the time-like component or the full four vector. The systems covered here are referred to as quasirelativistic, which means retardation, regularization, and form factors are not included. Since the model used in this paper describes mesons which cannot decay physically, the equations must describe stable states. We find that this requirement is not always satisfied, and give a complete discussion of the conditions under which the various equations give unphysical, unstable solutions.
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Mehrban, Hossein. "Matter-antimatter asymmetry of b-quark and B-meson decays." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324379.
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Elliott, Louie C. "Regular and Hybrid Mesons in a Non-RelativisticConstituent Quark Model." NCSU, 1998. http://www.lib.ncsu.edu/theses/available/etd-19980807-164043.
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We investigate q-qbar and q-qbar-g mesons with regularand exotic quantum numbers in a non-relativisticconstituent quark model. Simple harmonic oscillator statesare used as radial wave functions, which allows for analyticmatrix elements. Employing a diagonalization withvariational approach, the resulting generalizedeigenvalue problem is solved for the meson bound states.With a minimal number of parameters, we are able to describe the non-exotic meson spectrum within a few percent.Predictions are also made for the masses of hybrid mesons,with the lowest lying 1-+ u-ubar-g mass of 1.26 MeV.
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McGovern, J. A. "Strange baryons in a chiral quark-meson model." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233064.
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Morales, Patrícia Soares [UNESP]. "Limite de acoplamento forte da QCD e a interação méson-méson." Universidade Estadual Paulista (UNESP), 2002. http://hdl.handle.net/11449/91868.
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morales_ps_me_ift.pdf: 900348 bytes, checksum: 11b8ab9b4c422ec3a42face91d5074e6 (MD5)O mecanismo de rearranjo de tubos de fluxo predito no limite de acoplamento forte da formulação Hamiltoniana da QCD na rede foi implementado num modelo de quarks constituintes e suas consequências investigadas para o espalhamento méson-méson. O rearranjo de tubos de fluxo leva a efeitos similares aos tradicionais efeitos de troca de quarks com troca de um glúon em interações hádron-hádron. Contudo, enquanto o primeiro está relacionado ao regime de confinamento da QCD, o último está relacionado ao regime de liberdade assintótica desta teoria. Mostra-se aqui que ambos mecanismos levam a resultados qualitativamente similares quando o potencial de rearranjo pode ser escrito como a soma de interações locais quark-quark, antiquark-antiquark e quark-antiquark. Para interações gerais, não locais e de longo alcance, o rearranjo de tubos de fluxo leva a resultados qualitativa e quantitativamente diferentes dos resultados de troca de quarks com troca de um glúon. As consequências disso para a fenomenologia das interações hádron-hádron são discutidas.
The mechanism of link rearrangement predicted in the strong coupling limit of Hamiltonian lattice QCD is implemented in a constituent quark model and its consequences for meson-meson scattering are investigated. Link rearrangement leads to effects similar to the traditional quark exchange with one gluon exchange in hadron-hadron interactions. However while the first is related to the confinement regime of QCD, the latter is related to the asymptotic freedom regime of this theory. It is shown here that both mechanisms lead to identical qualitative results when the rearrangement potential can be written as a sum of local quark-quark, antiqurk-antiquark e quark-antiquark. For general, long-range nonlocal interactions, link rearrangement leads to results qualitative and quantitatively different from those of quark exchange with one gluon exchange. The consequences of this for the phenomenology of hadron-hadron interactions are discussed.
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DeWitt, Martin Alan. "The Spectrum and Decays of Scalar Mesons in the Light-Front Quark Model." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-03282008-142316/.
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We use the light-front quark model to investigate the structure of the scalar mesons, mainly focusing on the three heavy isoscalar states f0(1370), f0(1500), and f0(1710). We comput the spectrum of scalar mesons by diagonalizing a relativized, QCD-inspired model Hamiltonian written in a basis of 25 simple harmonic oscillator states. The masses are then used to perform a mixing analysis which assumes that the heavy isoscalars are mixtures of quarkonia and the scalar glueball. The resulting quark-glue content is used along with the meson wave functions determined from the spectrum to compute the decay rates to pairs of pseudoscalar mesons (two pions, two kaons, two eta mesons). We find that when the glueball contributions to the decays are ignored, the results are in poor agreement with the available data. However, when we estimate the effect of including the glueball contributions in the decays, a solution can be found that matches the data quite well. In this solution, the f0(1710) is mostly glueball (78%) while the f0(1500) and f0(1370) are mostly mixtures of quarkonia. Additionally, in this solution the glueball contributions to kaon and eta final states are significant, while the contributions to the pion final state is negligible. This finding is in agreement with Chanowitz who uses chiral perturbation theory to show that the amplitude for a scalar glueball to decay to a quark-antiquark pair is proportional to the quark mass. This results in a suppression of the pion decay channel compared to the kaon and eta decay channels.
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Arndt, Daniel. "Light-Cone Quark Model Analysis ofPseudoscalar and Vector Mesons for Radially Excited States." NCSU, 1999. http://www.lib.ncsu.edu/theses/available/etd-19990518-132243.
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We present a relativistic constituent quark model to analyze the mass spectrum and hadronic properties of radially excited u and d quark sector mesons.Using a simple Gaussian function as a trial wave function for the variational principle togetherwith a QCD motivated Hamiltonian, including not only the Coulomb and confiningpotential but also a relativistic corrected hyperfine interaction term, we obtain the mass spectrum consistent with the experimental data. To do the same for several observables such as decay constants and form factors it seems necessary to include bothDirac and Pauli form factors on the level of constituentquarks. Taking into account these quark form factorswe thus present the generalized formulas for the rho mesondecay constant and the rho meson form factors as well asthe $\pi\gamma$ transition form factor.We alsopredict several hadronic properties for the radiallyexcited states.
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Wunderlich, Falk. "Photoemissivity near a chiral critical point within the quark-meson model." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233657.
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The interplay of thermodynamic properties of strongly interacting matter and its emission of photons is investigated. For this purpose the Lagrangian of the quark meson model (in the literature also dubbed "linear sigma model" or "linear sigma model with quarks") is extended by an electromagnetic sector. Based on this extended Lagrangian both the grand-canonical potential and the generating functional of correlation functions are calculated in a consistent manner. From the former, the phase structure and various thermodynamical properties are determined. Especially, the dependence of certain landmarks (critical point, intersections of the phase boundary with the coordinate axes, etc.) of the phase diagram with respect to the model parameters is investigated in detail. With the help of the generating functional in turn, the photon propagator can be computed whose imaginary part is connected to the emission rate of photons. The leading order of the result with respect to the number of participating particles and the power of the quark-meson coupling is expressed in terms of tree level diagrams, which are calculated likewise. On this basis, the photon emissivity with respect to temperature, chemical potential and photon frequency is calculated and analyzed addressing various questions. The dependence of the particle masses with respect to temperature and chemical potential leaves notable imprints on the emissivities of the individual production processes. Especially a first-order phase transition can easily be identified, since, there, the emissivity may jump - depending on the temperature - by a factor of about ten. Contrarily, within our analysis, we do not find signatures in the photon emissivities that specifically mark a critical end point. Moreover, it is investigated on which parameters the photon emission rate depends in the low- and high-frequency regions. With these results the behavior of the emissivity with respect to temperature and chemical potential can be understood and many peculiarities of the emissivities can be explainedDas Zusammenspiel der thermodynamischen Eigenschaften von stark wechselwirkender Materie und deren Emission von Photonen wird untersucht. Dazu wird die Lagrangedichte des Quark-Meson-Modells (auch: Linear-Sigma-Modell oder Linear-Sigma-Modell mit Quarks) um einen elektromagnetischen Sektor erweitert. Aus der so erweiterten Lagrangedichte werden auf konsistente Weise sowohl das großkanonische Potential als auch das erzeugende Funktional der Korrelationsfunktionen ermittelt. Aus ersterem werden die Phasenstruktur des Modells sowie zahlreiche thermodynamische Eigenschaften berechnet. Insbesondere wird die Abhänigkeit einiger Orientierungspunkte (kritischer Punkt, Schnittpunkte der Phasengrenze mit den Koordinatenachsen usw.) des Phasendiagramms von den Modellparametern detailiert untersucht. Mit Hilfe des erzeugenden Funktionals wiederum kann der Photonenpropagator bestimmt werden, dessen Imaginärteil mit der Emissionsrate von Photonen zusammenhängt. Die führende Ordnung in einer Entwicklung nach der Anzahl der beteiligten Teilchen und der Potenz der Quark-Meson-Kopplung lässt sich durch Baumgraphen-Diagramme darstellen, die ebenfalls berechnet werden. Auf dieser Basis wird die Photon-Emissivität in Abhängigkeit von Temperatur, chemischem Potential und Photon-Frequenz berechnet und unter verschiedenen Gesichtspunkten analysiert. Die Abhängigkeit der Teilchenmassen von Temperatur und chemischem Potential hinterlässt teilweise ausgeprägte Signaturen in den Emissivitäten der einzelnen sub-Prozesse. Insbesondere ein Phasenübergang erster Ordnung zeigt sich deutlich, da an diesem die Emissivität - abhänging von der Temperatur - um einen Faktor der Größenordnung zehn springen kann. Jedoch finden wir im Rahmen dieser Analyse keine spezifischen Signaturen in den Photonen-Emissivitäten, die einen kritischen Punkt auszeichnen. Des weiteren wird untersucht von welchen Parametern die Photonen-Emissionsrate in den Bereichen niedriger oder hoher Photonen-Frequenzen abhängt. Mit diesen Ergebnissen kann das Verhalten der Emissivität in Abhängigkeit von Temperatur und chemischem Potential gut verstanden und zahlreiche Auffälligkeiten in den Emissivitäten erklärt werden
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Arndt, Daniel. "Light-cone quark model analysis of pseudoscalar and vector mesons for radially excited states." Raleigh, NC : North Carolina State University, 1999. http://www.lib.ncsu.edu/etd/public/etd-3522131849921371/etd.pdf.
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Blundell, Harry G. (Harry Grahame) Carleton University Dissertation Physics. "Meson properties in the quark model; a look at some outstanding problems." Ottawa, 1996.
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Karlsen, Robert Einar. "The constituent quark model, PCAC consistency and the nonleptonic weak decays of mesons and baryons." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186194.
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We use the nonperturbative techniques of current algebra and PCAC (partial conservation of axial-vector currents) to compute the nonleptonic weak decays K → 2π and 3π, as well as the two-body and nonresonant three-body decays of the charmed D and F(D(s)) mesons. In the case of two-body decays, the constituent quark model is employed to calculate the resulting unphysical meson-meson reduced matrix elements. Using an analogous current algebra - PCAC prescription, the three-body meson decays are expressed in terms of the previously determined two-body amplitudes. We utilize the pole model to extract baryon-baryon reduced matrix elements from the B → B' π and B'γ weak decays, which are then also computed in the constituent quark model. We make predictions for more than sixty decays with essentially no free parameters and, in most cases, find reasonable agreement with the data.
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Folador, Bruna Cesira. "Correções relativísticas ao modelo de quarks no espalhamento J/ψ-nucleon." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/117765.
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O Método do Grupo Ressonante (RGM) é um método utilizado no estudo da interação hádron-hádron, na qual não são desprezados os graus de liberdade internos destas partículas. Nesta dissertação estudaremos os efeitos associados `a interação entre um quark pesado Q com outro leve q no potencial de troca de um gluón chamado de One Gluon Exchange Potencial (OGEP), tradicionalmente obtido a partir de um potencial relativístico de interação do modelos de quarks, fazendo uma expansão em potências de momentos nos espinores constituintes (potencial de Fermi-Breit). Faremos uma aproximação semi-relativística para o quark leve q, enquanto que o quark pesado Q será considerado não-relativístico. Este potencial semi-relativístico será usado no RGM para estudar a interação entre charmônios e nucleons como no caso da interação J/ψ-nucleon.The Resonating Group Method (RGM) is used in hadron-hadron interactions, when internal degrees of freedom of composite particles can’t be neglected. In this dissertation we shall study the effects associated with the interaction between a heavy quark Q with a light quark q, using the the One Gluon Exchange Potential (OGEP) traditionally obtained from a relativistic interaction potential in the quark model, by an expansion in powers of momentum of the constituent spinors (potential Fermi-Breit). We will make a semi-relativistic approach for light quark q, while the heavy quark Q will be considered non-relativistic. This semi-relativistic potential will be used in the RGM to study the interaction between charmonia and nucleons as the case J/ψ-nucleon interaction.
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Tandogan, Asli. "Study Of Dsj(2317) And Dsj(2460) Meson Properties Within The Quark Model And Qcd Sum Rules." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608592/index.pdf.
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The recently discovered DsJ(2317) and DsJ(2460) mesons had stimulated many theoretical and experimental studies due to their unexpected properties. In this thesis, we make a review of the predictions on the properties of these mesons
using the quark model and QCD Sum Rules. We studied different models about the structure of these mesons, which are suggested because of their unexpected properties. Moreover, using the quark model which implies that the structure of DsJ meson as cs and QCD Sum Rules method, we investigated the semileptonic decay DsJ(2317)-->D0 l nu.
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Manzoni, Luiz ALberto. "Simetria quiral, modelos de quarks e espalhamento píon-píon no formalismo fock-tani /." São Paulo, 1995. http://hdl.handle.net/11449/132721.
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Orientador: Gastão Inácio KreinBanca: Vicente Pleitez
Banca: Manoel Roberto Robilotta
Resumo: Consideramos modelos de quarks quirais para estudar o espalhamento 'PI-PI' a baixas energias. A quebra dinâmica da simetria quiral é estudada através do método variacional de Bogoliubov-Valatin. Dentro deste esquema, a estrutura de quarks dos pions considerados como bosons de Goldstone é obtida. Através do formalismo Fock-Tani obtemos um Hamiltoniano efetivo em termos dos graus de liberdade piônicos e a partir deste obtemos a amplitude de espalhamento 'PI-PI' no limiar. Usando a propriedade de "crossing" da matriz de espalhamento, o resultado é estendido para energias além do limiar. O resultado concorda com aquele obtido por Weinberg no contexto da álgebra de correntes
Abstract: We consider chiral quark models to study 'PI-PI' scattering at low energies. The dynamical chiral symmetry breaking is studied by means of the Bogoliubov-Valatin variational method. Within such a scheme, the quark structure of the pions considered as Goldstone bosons is obtained. By means of the Fock-Tani formalism we obtain an effective Hamiltonian in terms of pion degrees of freedom and from this we obtain the 'PI-PI' scattering matrix at threshold. Using the crossing property of the scattering matrix, the result is extended to energies beyond threshold. The result agrees with the one obtained by Weinberg in context of current algebra
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Di, Pierro Massimo. "B physics from lattice simulations." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297379.
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NEBAUER, REGINA. "Les proprietes des quarks et mesons a densite et temperature finies dans le cadre du modele njl." Nantes, 2000. http://www.theses.fr/2000NANT2068.
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Le modele de nambu et jona-lasinio (njl) doit etre la base pour la simulation de l'expansion et hadronisation d'un plasma de quarks. Le point fort du modele njl etant l'implementation exacte de la symetrie chirale et de sa brisure spontanee, le point faible est le confinement. Comme la plupart des modeles effectives, le modele njl ne decrit pas le confinement. Les avantages et desavantages du modele njl en etant une approximation de qcd a basse energie seront discute en detail au cours de l'expose afin de bien determiner les possibilites mais aussi les limites du modele. Dans le cadre de cette these une etude detaillee des proprietes thermodynamique du modele njl a ete elabore. La connaissance profonde des proprietes d'un systeme en equilibre est indispensable avant passer aux systemes hors equilibre, comme par exemple un plasma en expansion. La transition de phase la plus importante dans le cas d'un plasma de quark, est la transition de phase chirale. Un autre processus important est la hadronisation. Afin d'etudier les phenomenes lies aux transitions de phases, la connaissance du diagramme des phases et des proprietes des hadrons dans le milieu est indispensable. Le modele njl a l'avantage de permettre des calculs a densite et temperature finies. Des comparaisons avec des calculs qcd sur reseaux montrent, que le modele njl decrit correctement la brisure et la restauration de la symetrie chirale. Nous allons presenter un diagramme des phases du modele njl a trois saveurs. La dependance des parametres de ce diagramme des phases sera discuter afin de completer cette etude et de determiner la fiabilite des resultats. Nous nous interessons aussi au proprietes des mesons a temperature et densite finie dans le cadre du modele njl. Nous avons plus specialement etudie et comparer les resultats des differentes versions du modele njl afin de trouver la version la plus adaptee a notre probleme et en meme temps la plus realiste dans cette domaine. Pour cela nous avons compare par exemple la masse des kaons dans un milieu chaud et dense avec des donnees des experiences au gsi et avec autres approches comme rmf et chpt. Un dernier point qui sera evoque dans cette these est la zone de basse temperature et haute densite dans le diagramme des phases. Dans cette region la formation d'un condensat de diquarks est attendue. Ce condensat est responsable pour la supraconductivite de couleurs. Meme si cette zone n'est pas specialement d'interet pour les collisions d'ions lourds, il y a des applications dans l'astrophysique. Ensemble avec la matiere etrange, qui est discute brievement dans cette these, la supraconductivite de couleurs fait une sorte d'interface entre la physique des collisions d'ions lourds et l'astrophysique.
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Staśto, Anna. "QCD analysis of deep inelastic lepton-hadron scattering in the region of small values of the Bjorken parameter x." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4515/.
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We present the new framework based on BFKL and DGLAP evolution equations in which the leading in(Q(_2)) and in(l/x) terms are treated on equal footing. We introduce a pair of coupled integro-difFerential equations for the quark singlet and the unintegrated gluon distribution. The observable structure functions are calculated using high energy factorisation approach. We also include the sub-leading in (l/x) effects via consistency constraint. We argue that the use of this constraint leads to more stable solution to the Pomeron intercept than that based on the NLO calculation of the BFKL equation alone and generates resummation to all orders of the major part of the subleading in (l/x) effects. The global fit to all available deep inelastic data is performed using a simple parametrisation of the non-perturbative region. We also present the results for the longitudinal structure function and the charm component of the F(_2) structure function. Next; we extend this approach to the low Q(^2) domain. At small distances we use the perturbative approach based on the unified BFKL/DGLAP equations and for large distances we use Vector Meson Dominance Model and, for the higher mass qq states, the additive quark approach. We show the results for the total cross section and for the ratio of the longitudinal and transverse structure functions. Finally, we calculate the dijet production and consider the decorrelation effects in the azimuthal distributions caused by the diffusion in the transverse momentum k(_r) of the exchanged gluon. Using the gluon distribution which is fixed by the fit to the DIS data we are able to make absolute predictions. We show the results for the dF(_r)/dɸ, the total cross section and also the distributions in Q(^2) as well as in the longitudinal momentum fraction of the gluon. Our theoretical predictions are confronted with the measurements made using ZEUS detector at HERA.
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Wunderlich, Falk [Verfasser], Burkhard [Akademischer Betreuer] Kämpfer, Burkhard [Gutachter] Kämpfer, Dominik [Gutachter] Stöckinger, and Bengt [Gutachter] Friman. "Photoemissivity near a chiral critical point within the quark-meson model / Falk Wunderlich ; Gutachter: Burkhard Kämpfer, Dominik Stöckinger, Bengt Friman ; Betreuer: Burkhard Kämpfer." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://d-nb.info/1154680290/34.
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Wunderlich, Falk [Verfasser], Burkhard [Akademischer Betreuer] Kämpfer, Burkhard Gutachter] Kämpfer, Dominik [Gutachter] [Stöckinger, and Bengt [Gutachter] Friman. "Photoemissivity near a chiral critical point within the quark-meson model / Falk Wunderlich ; Gutachter: Burkhard Kämpfer, Dominik Stöckinger, Bengt Friman ; Betreuer: Burkhard Kämpfer." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233657.
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Michaud, Yonnel. "Etude phénoménologique de la réaction d'échange de charge (pi)-p -> (pi)[n à haute énergie]." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10097.
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La presente these est consacree a l'etude de la reaction d'echange de charge pion negatif proton donne pion nul neutron. Cette reaction fait partie des processus quasi-elastiques, caracterises par de petits moments transferes, et donc non interpretables par la chromodynamique quantique. Le modele de glauber, utilise avec succes dans le cadre de la diffusion elastique, est exploite ici pour l'etude de la reaction d'echange de charge. Une interaction effective entre quarks, incluant un terme central et un terme spinorbite, est employee afin de rendre compte de l'echange du meson rho. Les resultats obtenus permettent de conclure a la nature diffractive de la reaction etudiee, mais ne permettent pas de determiner avec precision les rayons moyens des densites de quarks interagissants
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Zacchi, Andreas [Verfasser], Carsten [Akademischer Betreuer] [Gutachter] Greiner, and Jürgen [Gutachter] Schaffner-Bielich. "Thermal evolution of massive compact strange objects in a SU(3) chiral Quark Meson Model / Andreas Zacchi ; Gutachter: Jürgen Schaffner-Bielich, Carsten Greiner ; Betreuer: Carsten Greiner." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2017. http://d-nb.info/113827688X/34.
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Tayduganov, Andrey. "Electroweak radiative B-decays as a test of the Standard Model and beyond." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00648217.
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Recently the radiative B-decay to strange axial-vector mesons, B--> K1(1270) gamma, was observed with a rather large branching ratio. This process is particularly interesting as the subsequent K1-decay into its three-body final state allows us to determine the polarization of the photon, which is mostly left(right)-handed for Bbar(B) in the Standard Model while various new physics models predict additional right(left)-handed components. In this thesis, a new method is proposed to determine the polarization, exploiting the full Dalitz plot distribution, which seems to reduce significantly the statistical errors on the polarization parameter lambda_gamma measurement.This polarization measurement requires, however a detailed knowledge of the K1--> K pi pi strong interaction decays, namely, the complex pattern of the various partial wave amplitudes into several possible quasi-two-body channels as well as their relative phases. A number of experiments have been done to extract all these information while there remain various problems in the previous studies. In this thesis, we investigate the details of these problems. As a theoretical tool, we use the 3P0 quark-pair-creation model in order to improve our understanding of strong K1 decays.Finally we try to estimate some theoretical uncertainties: in particular, the one coming from the uncertainty on the K1 mixing angle, and the effect of a possible ''off-set'' phase in strong decay S-waves. According to our estimations, the systematic errors are found to be of the order of sigma(lambda_gamma)^th<20%. On the other hand, we discuss the sensitivity of the future experiments, namely the SuperB factories and LHCb, to lambda_gamma. Naively estimating the annual signal yields, we found the statistical error of the new method to be sigma(lambda_gamma)^stat<10% which turns out to be reduced by a factor 2 with respect to using the simple angular distribution.We also discuss a comparison to the other methods of the polarization measurement using processes, such as B--> K* e^+ e^-, Bd--> K* gamma and Bs--> phi gamma, for the determination of the ratio of the Wilson coefficients C7gamma^'eff/C7gamma^eff. We show an example of the potential constraints on C7gamma^'eff/C7gamma^eff. in several scenarios of supersymmetric models.
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Vale, Silva Luiz Henrique. "Phénoménologie de modèles à symétrie droite-gauche dans le secteur des quarks." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS249/document.
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Bien qu'ayant beaucoup de succès pour décrire la grande variété de phénomènes de la physique des particules, le Modèle Standard (MS) laisse certaines propriétés de la nature sans explication. Ici, nous allons mettre l'accent sur le traitement différent des chiralités de type gauche et droite dans le cadre du MS. Une façon naturelle d'expliquer cela est de plonger le MS dans un modèle plus fondamental, capable de traiter les chiralités d'une manière symétrique. Cette classe de modèles, connue sous le nom de "modèles à symétrie droite-gauche" (LR models, en anglais), introduit une nouvelle interaction qui couple préférentiellement aux champs "droitiers". Puis, à une haute échelle d'énergie, la symétrie reliant droite et gauche est brisée spontanément donnant naissance au MS et aux phénomènes de violation de symétrie de parité. La manière spécifique par laquelle le mécanisme Brout-Englert-Higgs (BEH) se produit dans les modèles LR peut être sondée par des observables électrofaibles de précision, ce qui sert de premier test de l'extension du MS dans le secteur électrofaible. Comme conséquence du mécanisme BEH dans les modèles LR, de nouveaux bosons de jauge sont présents. Ce sont W’ et Z’, censés être beaucoup plus lourds que les bosons de jauge W et Z afin d'expliquer pourquoi ils n'ont jamais été vus jusqu'à présent. Ces nouvelles particules sont accompagnées d'une riche phénoménologie, comme de nouvelles sources de violation de CP au-delà de celle du MS. En outre, un nouveau secteur scalaire neutre introduit des courants qui changent la saveur (FCNC, en anglais) au niveau des arbres, un processus fortement restreint dans le MS, où il arrive seulement à l'ordre des boucles. L'existence de FCNCs fournit des contraintes extrêmement puissantes sur les modèles LR, et mérite donc une attention spéciale, en particulier lors du calcul des corrections venant de la QCD. Nous calculons donc les corrections au Next-to-Leading Order des effets à de courtes distances venant de la QCD aux contributions du modèle LR aux observables liées au mélange de mésons neutres et sensibles donc aux FCNC.Ensuite, nous considérons l'étude phénoménologique des modèles LR afin de tester leur viabilité et leur structure. Plus particulièrement, nous considérons le cas où des doublets scalaires sont responsables de la brisure du groupe de jauge des modèles LR. A cet effet, nous menons une étude combinée des observables de précision électrofaible, des bornes directes sur la masse des nouveaux bosons de jauge et des observables qui dérivent de l'oscillation des mésons neutres, dans le cas plus simple où la matrice de mixing dans le secteur droit est égal à la matrice CKM. Ces observables sont combinées dans le cadre du paquet CKMfitter d'analyse statistique. La combinaison de différentes classes d'observables doit prendre en compte la particularité des incertitudes théoriques, qui ne sont pas de nature statistique comme d'autres sources d'incertitude. A ce propos, nous considérons aussi la comparaison de différentes modèles d'incertitude théorique, afin de trouver des méthodes bien adaptées à la situation actuelle de notre connaissance des incertitudes théoriques impliquées dans un fit global en physique de la saveurThough very successful in explaining a wide variety of particle physics phenomena, the Standard Model (SM) leaves unexplained some properties of nature. Here we focus on the different behaviours of left- and right-handed chiralities, or in other words the violation of parity symmetry. A possible and somewhat natural avenue to explain this feature is to embed the SM into a more symmetric framework, which treats the chiralities on equal footing. This class of models, the Left-Right (LR) Models, introduces new gauge interactions that couple preferentially to right-handed fields. Then, at an energy scale high enough, LR symmetry is spontaneously broken through the Brout-Englert-Higgs (BEH) mechanism, thus giving origin to the SM and to parity violating phenomena. The specific way in which the BEH mechanism operates in LR Models can be probed by EW Precision Observables, consisting of quantities that have been very accurately measured, serving as a first test of consistency for extensions of the SM in the EW sector. We revisit a simple realization of LR Models containing doublet scalars, and consider the phenomenological study of this doublet scenario in order to test the viability and structure of the LR Models. In particular, there is a rich phenomenology associated to the new gauge bosons W’ et Z’ introduced by LR Models, such as new sources of CP violation beyond the one of the SM. Moreover, the extended neutral scalar sector introduces Flavour Changing Neutral Couplings (FCNC) at tree level, which are strongly suppressed in the SM where they arrive first at one loop. FCNCs typically lead to extremely powerful constraints since they contribute to meson-mixing processes, and therefore deserve close attention. For this reason, we consider the calculation of short-distance QCD effects correcting the LR Model contributions to meson-mixing observables up to the Next-to-Leading Order (NLO), a precision required to set solid lower bounds on the LR Model scales. Finally, we combine in a global fit electroweak precision observables, direct searches for the new gauge bosons and meson oscillation observables in the simple case where the right-handed analogous of the CKM mixing-matrix is equal to the CKM matrix itself (a scenario called CKMfitter symmetry). The full set of the observables is combined by using the CKMfitter statistical framework, based on a frequentist analysis and a particular scheme for modeling theoretical uncertainties. We also discuss other possible modelings of theoretical uncertainties in a prospective study for future global flavour fits made by the CKMfitter Collaboration
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Renard, Frédéric. "Étude de la structure du nucléon via la photoproduction de mésons pseudoscalaires à GRAAL : mesure des sections efficaces et des asymétries de faisceau des réactions [gamma]+p->p+[pi]°et [gamma]+p->p+[éta] pour E[nu] compris entre 550 et 1100 MeV." Grenoble 1, 1999. http://www.theses.fr/1999GRE10270.
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L'experience graal est consacree a la comprehension de la structure dynamique du nucleon et de ses etats excites, les resonances baryoniques. L'etude experimentale des reactions de photoproduction de mesons sur le nucleon est accomplie a l'aide d'un faisceau de photons polarises et d'un multi-detecteur 4. Le faisceau est produit par retrodiffusion compton de photons laser sur les electrons de 6 gev du synchrotron europeen a grenoble (l'esrf). Cette these porte sur l'analyse des premieres donnees acquises par la collaboration graal. Apres la caracterisation du faisceau et le calcul de la dose de photons etiquetes, l'analyse decrit les techniques d'identification des reactions de photoproduction des mesons 0 et. Les performances du systeme de detection, resolutions et efficacites, sont determinees a partir des mesures experimentales et des simulations. Les prises de donnees realisees en 1997 ont permis d'etudier les reactions p 0p et p p dans une gamme d'energie des photons allant de 550 a 1100 mev. L'analyse complete de ces deux canaux a ete effectuee et des resultats finaux pour la section efficace d/d et l'observable de polarisation ont ete obtenus. L'ensemble des corrections aux donnees ainsi que l'evaluation des erreurs systematiques sont presentes en detail. L'asymetrie faisceau obtenue avec une polarisation lineaire des photons, a ainsi ete mesuree pour la premiere fois dans la production du. La section efficace du meme processus et les mesures obtenues pour la production de 0 ameliorent grandement la precision et la couverture cinematique de la base de donnees existante. Les observables de polarisation sont sensibles a des contributions tres petites, difficiles a discerner dans les mesures de section efficace. Ainsi, le rapport de branchement de la resonance n*(1520) dans le canal a pu etre determine avec une bonne precision: b = / t o t = (0,08 0,01)%. Ces resultats sont selectifs pour les modeles des hadrons et contribuent ainsi a l'amelioration de notre connaissance des baryons et des mesons.
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Baalouch, Marouen. "Dalitz analysis of the three-body charmless decay B0 → K0Sπ+π− with the LHCb spectrometer." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22652/document.
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Le travail présenté dans cette thèse concerne l’étude des désintégrations en trois corps sans quark charmé des mésons beaux neutres, dont l’état final contient un K0S. Ce travail de recherche s’est réalisé dans le cadre de l’expérience LHCb au LHC, en analysant un échantillon d’événements de 3 fb−1 collecté dans le Run I du LHC. L’analyse d’amplitude de la désintégration B0→K0Sπ+π− représente la partie principale de ce travail de thèse. La mesure des amplitudes est effectuée au moyen d’une étude du plan de Dalitz de la désintégration intégrée dans le temps sans étiquetage de la saveur de la particule belle. Nous avons mesuré les rapports d’embranchements relatives des désintégrations quasi-deux-corps à partir de cette analyse de Dalitz. Egalement, nous avons mesuré l’asymétrie CP directe des désintégrations quasi-deux-corps B0→K*+(892)π−, B0→K0*+(1430)π−, B0→K2*+(1430)π− et B0→f0(980)K0S. Nous avons observé pour la première fois l’asymétrie CP directe dans la désintégration B0→K*+(892)π− avec une signifiance supérieure à cinq déviations standard. Cette mesure est en accord avec la moyenne mondiale, avec une précision amélioréeStudies of charmless three-body decays of the neutral B mesons with a K0S in the final state are presented in this thesis. The analyses are performed with the full statistics recorded by the LHCb spectrometer during the Run I of the LHC. The amplitude analysis of the decay B0→K0Sπ+π− represents the main part of this thesis analysis. A time-integrated untagged Dalitz-Plot analysis of the decay is performed. The fit fractions of the quasi-two-body decays are obtained. Likewise, the direct CP asymmetries of the quasi-two-body decays B0→K*+(892)π−, B0→K0*+(1430)π−, B0→K2*+(1430)π− and B0→f0(980)K0S are obtained. The largest sensitivity is obtained for ACP (B0→K*+(892)π−). This measurement is the first observation of the CP asymmetry with a significance larger then five standard deviations. The measurement is in agreement with the world average, with an improved precision
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Elliott, Louie C. "Regular and hybrid mesons in a non-relativistic constituent quark model." 1998. http://www.lib.ncsu.edu/etd/public/etd-334016779852181/etd.pdf.
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Barbari, Sherif A. S. "Meson and dibaryon masses in a QCD based consistent quark model." Thesis, 1986. http://spectrum.library.concordia.ca/3671/1/NL30688.pdf.
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Wunderlich, Falk. "Photoemissivity near a chiral critical point within the quark-meson model." Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A30826.
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The interplay of thermodynamic properties of strongly interacting matter and its emission of photons is investigated. For this purpose the Lagrangian of the quark meson model (in the literature also dubbed "linear sigma model" or "linear sigma model with quarks") is extended by an electromagnetic sector. Based on this extended Lagrangian both the grand-canonical potential and the generating functional of correlation functions are calculated in a consistent manner. From the former, the phase structure and various thermodynamical properties are determined. Especially, the dependence of certain landmarks (critical point, intersections of the phase boundary with the coordinate axes, etc.) of the phase diagram with respect to the model parameters is investigated in detail.
With the help of the generating functional in turn, the photon propagator can be computed whose imaginary part is connected to the emission rate of photons. The leading order of the result with respect to the number of participating particles and the power of the quark-meson coupling is expressed in terms of tree level diagrams, which are calculated likewise. On this basis, the photon emissivity with respect to temperature, chemical potential and photon frequency is calculated and analyzed addressing various questions.
The dependence of the particle masses with respect to temperature and chemical potential leaves notable imprints on the emissivities of the individual production processes. Especially a first-order phase transition can easily be identified, since, there, the emissivity may jump - depending on the temperature - by a factor of about ten. Contrarily, within our analysis, we do not find signatures in the photon emissivities that specifically mark a critical end point. Moreover, it is investigated on which parameters the photon emission rate depends in the low- and high-frequency regions. With these results the behavior of the emissivity with respect to temperature and chemical potential can be understood and many peculiarities of the emissivities can be explained.Das Zusammenspiel der thermodynamischen Eigenschaften von stark wechselwirkender Materie und deren Emission von Photonen wird untersucht. Dazu wird die Lagrangedichte des Quark-Meson-Modells (auch: Linear-Sigma-Modell oder Linear-Sigma-Modell mit Quarks) um einen elektromagnetischen Sektor erweitert. Aus der so erweiterten Lagrangedichte werden auf konsistente Weise sowohl das großkanonische Potential als auch das erzeugende Funktional der Korrelationsfunktionen ermittelt. Aus ersterem werden die Phasenstruktur des Modells sowie zahlreiche thermodynamische Eigenschaften berechnet. Insbesondere wird die Abhänigkeit einiger Orientierungspunkte (kritischer Punkt, Schnittpunkte der Phasengrenze mit den Koordinatenachsen usw.) des Phasendiagramms von den Modellparametern detailiert untersucht. Mit Hilfe des erzeugenden Funktionals wiederum kann der Photonenpropagator bestimmt werden, dessen Imaginärteil mit der Emissionsrate von Photonen zusammenhängt. Die führende Ordnung in einer Entwicklung nach der Anzahl der beteiligten Teilchen und der Potenz der Quark-Meson-Kopplung lässt sich durch Baumgraphen-Diagramme darstellen, die ebenfalls berechnet werden. Auf dieser Basis wird die Photon-Emissivität in Abhängigkeit von Temperatur, chemischem Potential und Photon-Frequenz berechnet und unter verschiedenen Gesichtspunkten analysiert. Die Abhängigkeit der Teilchenmassen von Temperatur und chemischem Potential hinterlässt teilweise ausgeprägte Signaturen in den Emissivitäten der einzelnen sub-Prozesse. Insbesondere ein Phasenübergang erster Ordnung zeigt sich deutlich, da an diesem die Emissivität - abhänging von der Temperatur - um einen Faktor der Größenordnung zehn springen kann. Jedoch finden wir im Rahmen dieser Analyse keine spezifischen Signaturen in den Photonen-Emissivitäten, die einen kritischen Punkt auszeichnen. Des weiteren wird untersucht von welchen Parametern die Photonen-Emissionsrate in den Bereichen niedriger oder hoher Photonen-Frequenzen abhängt. Mit diesen Ergebnissen kann das Verhalten der Emissivität in Abhängigkeit von Temperatur und chemischem Potential gut verstanden und zahlreiche Auffälligkeiten in den Emissivitäten erklärt werden.
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Carroll, Jonathan David. "Applications of the octet baryon quark-meson coupling model to hybrid stars." 2010. http://hdl.handle.net/2440/58132.
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The study of matter at extreme densities has been a major focus in theoretical physics in the last half-century. The wide spectrum of information that the field produces provides an invaluable contribution to our knowledge of the world in which we live. Most fascinatingly, the insight into the world around us is provided from knowledge of the intangible, at both the smallest and largest scales in existence. Through the study of nuclear physics we are able to investigate the fundamental construction of individual particles forming nuclei, and with further physics we can extrapolate to neutron stars. The models and concepts put forward by the study of nuclear matter help to solve the mystery of the most powerful interaction in the universe; the strong force. In this study we have investigated a particular state-of-the-art model which is currently used to refine our knowledge of the workings of the strong interaction and the way that it is manifested in both neutron stars and heavy nuclei, although we have placed emphasis on the former for reasons of personal interest. The main body of this work has surrounded an effective field theory known as Quantum Hadrodynamics (QHD) and its variations, as well as an extension to this known as the Quark-Meson Coupling (QMC) model, and variations thereof. We further extend these frameworks to include the possibility of a phase transition from hadronic matter to deconfined quark matter to produce hybrid stars, using various models. We have investigated these pre-existing models to deeply understand how they are justified, and given this information, we have expanded them to incorporate a modern understanding of how the strong interaction is manifest.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1458960
Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2010
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Chatterjee, Sandeep. "Model Studies Of The Hot And Dense Strongly Interacting Matter." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2518.
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Ultra-relativisitic heavy ion collisions produce quark gluon plasma-a hot and dense soup of deconfined quarks and gluons akin to the early universe. We study two models in the context of these collisions namely, Polyakov Quark Meson Model (PQM) and Hadron Resonance Gas Model (HRGM).The PQM Model provides us with a simple and intuitive understanding of the QCD equation of state and thermodynamics at non zero temperature and baryon density while the HRGM is the principle model to analyse the hadron yields measured in these experiments across the entire range of beam energies.
We study the effect of including the commonly neglected fermionic vacuum fluctuations to the (2+1) flavor PQM model. The conventional PQM model suffers from a rapid phase transition contrary to what is found through lattice simulations. Addition of the vacuum term tames the rapid transition and significantly improves the model’s agreement to lattice data. We further investigate the role of the vacuum term on the phase diagram. The smoothening effect of the vacuum term persists even at non zero . Depending on the value of the mass of the sigma meson, including the vacuum term results in either pushing the critical end point into higher values of the chemical potential or excluding the possibility of a critical end point altogether. We compute the fluctuations(correlations) of conserved charges up to sixth(fourth) order. Comparison is made with lattice data wherever available and overall good qualitative agreement is found, more so for the case of the normalised susceptibilities. The model predictions for the ratio of susceptibilities approach to that of an ideal gas of hadrons as in HRGM at low temperatures while at high temperature the values are close to that of an ideal gas of massless quarks.
We examine the stability of HRGMs by extending them to take care of undiscovered resonances through the Hagedorn formula. We find that the influence of unknown resonances on thermodynamics is large but bounded. We model the decays of resonances and investigate the ratios of particle yields in heavy-ion collisions. We find that extending these models do not have much effect on hydrodynamics but the hadron yield ratios show better agreement with experiment. In principle HRGMs are internally consistent up to a temperature higher than the cross over temperature in QCD; but by examining quark number susceptibilities we find that their region of applicability seems to end even below the QCD cross over.