Дисертації з теми "Quarkons"
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Berrehrah, Hamza. "Propagation et collectivité des quarkonia dans le plasma de quarks et de gluons : vers la suppression de la suppression du J/ψ à hautes températures". Nantes, 2011. http://www.theses.fr/2011NANT2115.
Повний текст джерелаThe suppression of quarkonia has been studied as a probe of the quark gluon plasma (QGP) properties for 25 years. However, the comparison between experimental data and theoretical scenarios including suppression mechanisms is not very conclusive. An alternative track is to study not only the suppression but also the physical properties of quarkonia survivors in the QGP. In fact, recent SPS results showed a non-zero quarkonia elliptic flow. On the other hand, recent RHIC results suggest a strong thermalization of charm quarks in the medium. Therefore, it follows a small diffusion coefficient and a moderate final separation between the two constituents of the bound state. This would limit the J/ψ suppression (suppression of the J/ψ suppression) and motivate the interest to study the quarkonia dynamics in the QGP. This thesis focuses on the study of the physical aspects underlying the quarkonia propagation and collectivity in the QGP. The study is performed using a hydrodynamic transport model describing the stochastic evolution of a bound state in a hot fluid. The ingredients for this approach are, among others, the evaluation of the elastic and inelastic quarkonium-gluon/quark/hadron scattering processes, and a relevant estimation of the collisional energy losses and stochastic forces of the thermal bath. To conduct this study, we developed a theoretical framework by combining analytical calculations based on pQCD, phenomenological considerations and results from lQCD. The role of elastic scattering process during the quarkonia propagation in the QGP has been demonstrated in our study. In addition, elements that characterize the quarkonia collectivity in the medium were obtained
Muramatsu, Hajime Skwarnicki Tomasz. "Photon spectroscopy of heavy quarkonia." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2004. http://wwwlib.umi.com/cr/syr/main.
Повний текст джерелаBASTOS, Cristiano Costa. "Química com quarks." Universidade Federal de Pernambuco, 2007. https://repositorio.ufpe.br/handle/123456789/8777.
Повний текст джерелаAlgumas propriedades da química de quarks podem ser obtidas realizando cálculos ab initio Hartree-Fock para átomos com carga nuclear fracionária e moléculas formadas por estes átomos. Obtivemos o estado fundamental e o primeiro estado excitado para os átomos de sódio, lítio, berílio e magnésio interagentes com quarks. Isto sugere que transições eletrônicas podem ser usadas como guia para detecção de quarks livres. Analisamos a variação da energia de ligação eletrônica com a carga nuclear para as séries isoeletrônicas de átomos com carga nuclear fracionária A±2/3 e A±1/3 (A = H, Li, Na, P and Ca). Isto mostra que partículas de cor não confinadas preferem se ligar a átomos pesados e o par quark-antiquark pode ser estabilizado na presença da matéria atômica
Rakotozafindrabe, Andry. "Etude de l'effet d'écrantage de couleur dans un plasma de quarks et de gluons sur les taux de production des quarkonia dans les collisions d'ions lourds auprès de l'expérience PHENIX." Phd thesis, Ecole Polytechnique X, 2007. http://pastel.archives-ouvertes.fr/pastel-00003165.
Повний текст джерелаDevlin, Francis Robert. "Physics of heavy quarks." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319786.
Повний текст джерелаVeiga, J. S. "Propriedades da matéria nuclear em modelos de quarks constituintes /." São Paulo, 1996. http://hdl.handle.net/11449/132865.
Повний текст джерелаKoempel, John Paul. "Exclusive Production of Quarkonia and Generalized Parton Distributions." Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/319337.
Повний текст джерелаPh.D.
The understanding of the nucleon is as of yet not complete. In particular, the contribution of the gluon content is not well understood. Utilizing the framework of Generalized Parton Distributions enables predictions to be made if some information on them is known. We investigated exclusive photo and electroproduction of heavy vector mesons (the quarkonia J/ψ and ϒ), which can give access to the currently poorly constrained gluon distribution Eg. For this reason, we implemented a model for it with several variants in order to represent a spread of plausible distributions. We used current experimental results for exclusive φ and ρ0 production to test our variants for Eg. For quarkonium production, the analytic calculation of the Leading Order production amplitudes was performed, verifying results published previously, in particular confirming that in the non-relativistic collinear approximation there is no access to the polarized or gluon helicity flip distributions, i.e. Hg and HgT. Numerical results for both the Leading Order and, in the case of photoproduction, also Next-to-Leading Order amplitudes were calculated, based on our Leading Order amplitudes and already existing Next-to-Leading Order expressions. The observables we looked at are the unpolarized cross section, spin density matrix elements, and two spin-asymmetries --- the transverse single-spin asymmetry An, and a newly discussed double-spin asymmetry ALS, which we identified as a very promising observable for measuring Eg. We find that in the case of J/ψ photoproduction higher order corrections seem not well under control, while for ϒ production the numerical results become much more stable.
Temple University--Theses
Smith, Jason. "Quarks and antiquarks in nuclei /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/9750.
Повний текст джерелаLeyva, Alfonso. "Strahlungskorrekturen zu Polarisationsobservablen schwerer Quarks." [S.l. : s.n.], 2000. http://ArchiMeD.uni-mainz.de/pub/2000/0128/diss.pdf.
Повний текст джерелаHiguchi, Katsuichi. "Electroweak Interaction with Singlet Quarks." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/152527.
Повний текст джерелаÜnalan, Zeynep. "A measurement of the top quark's charge." Diss., Connect to online resource - MSU authorized users, 2008.
Знайти повний текст джерелаGuerin, F. "Sonde muonique et instrumentation associée pour l'étude du plasma de quarks et de gluons dans l'expérience ALICE." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2006. http://tel.archives-ouvertes.fr/tel-00132781.
Повний текст джерелаMoreno, Torres Daniel. "Non-relativistic bound states in QCD: towards the N3LL heavy quarkonium spectrum." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667376.
Повний текст джерелаMauser, Marcus. "Polarisationseffekte in semileptonischen Zerfällen schwerer Quarks." [S.l. : s.n.], 2001. http://ArchiMeD.uni-mainz.de/pub/2001/0051/diss.pdf.
Повний текст джерелаJain, Ambar. "Heavy quarks in effective field theories." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53228.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 279-290).
Heavy quark physics serves as a probe to understand QCD, measure standard model parameters, and look for signs of new physics. We study several aspects of heavy quark systems in an effective field theory framework, including both phenomenological and formal applications. Phenomenological applications include the leading calculation of penguin amplitudes in charmless non-leptonic B-decays to light mesons, including power suppressed effects that are numerically enhanced by the chiral condensate. We compare our determination of the penguin amplitudes with the experimental results. Also, we calculate the heavy quark jet function at two loops, which is an important ingredient for the next-to-next-to-leading-log invariant-mass distribution of jets induced by tt pair production at a future linear collider. Formal applications include: a definition of top mass relevant for measurements that use top induced jets, a new renormalization group equation in an infrared scale intrinsic to heavy quark masses and its generalization for QCD matrix elements, a threshold mass definition which smoothly connects to the MS mass, and a new method to analyze renormalons in the operator product expansion.
by Ambar Jain.
Ph.D.
Enström, Daniel. "Aspects of quarks in exotic matter." Licentiate thesis, Luleå tekniska universitet, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16915.
Повний текст джерелаGodkänd; 1999; 20070321 (ysko)
Geng, Chaqiang. "Composite models of quarks and leptons." Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/76097.
Повний текст джерелаPh. D.
Boyd, Graham John. "Quarks and hadrons on the lattice." Master's thesis, University of Cape Town, 1990. http://hdl.handle.net/11427/15902.
Повний текст джерелаThere is a short introduction to the ideas of lattice theory, followed by an equally brief look at pure gauge QCD on the lattice. More details for either of these may be found in the references cited in each section, as well as in [143]. The bulk of this work deals with the problems encountered in placing fermions on to the lattice, and the techniques used for this purpose. The Nielsen-Ninomiya theorem is introduced, with a detailed treatment thereof relegated to an appendix. The two main fermion techniques, due to Wilson (1974); and Kogut and Susskind (1975) are dealt with in some detail. This is followed by a discussion of the construction of hadrons on the lattice, using either Wilson or Kogut-Susskind fermions. There is a chapter covering the algorithms used in numerical simulations of lattice QCD, with some examples illustrating them. The thesis concludes with a discussion of the results obtained thus far on the hadron spectrum, in both the quenched approximation as well as those obtained using dynamical quarks.
Agudelo, David Felipe Tamayo. "Materia de quarks a temperatura finita." reponame:Repositório Institucional da UFSC, 2013. https://repositorio.ufsc.br/handle/123456789/106802.
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A constitução dos objetos estelares continua sendo fonte de especulação. Varias hipótesis têm sido aventadas com relação a estrutura interna dos pulsares. Uma delas basei-se na conjetura de Bodmer-Witten, de que a altas densidades a matéria mias estável é formada por quarks desconfinados. Nesse caso, os pulsares seriam estrelas quarkiônicas, constituídas somente de quarks e léptons.O modelos mais comumente usado para descrever matéria de quarks é o modelo de sacola de MIT. Outro modelo, um pouco mais sofisticado é modelo dependente da densidade ou Quark mass density dependent model. Neste trabalho pretendemos comparar as equações de estado desses dois modelos, tanto a temperatura zero, como a temperatura finita. Essas equações de estado servem de input para as equações de Tlman-Oppenheimer-Volkoff (TOV), que são equações da relatividade geral para objetos homogéneos e de simetría esférica. Os resultados obtidos são os valores para massas e raios das estrelas.
Rosnet, P. "Les saveurs lourdes dans les collisions d'ions lourds ultra-relativistes." Habilitation à diriger des recherches, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00262436.
Повний текст джерелаHadjimichef, Dimiter. "Formalismo de Fock-Tani para a física hadrônica /." São Paulo, 1995. http://hdl.handle.net/11449/132802.
Повний текст джерелаBanca: Mahir Saleh Hussein
Banca: Yogiro Hama
Banca: Eliane Angela Veit
Banca: Rogério Rosenfeld
Resumo: O formalismo de teoria de campos Fock-Tani, o qual foi originalmente desenvolvido na física atômica para tratar sistemas em que os graus de liberdade internos dos átomos não podem ser desprezados, é generalizado para sistemas de hádrons compostos. Partindo da representação no espaço de Fock dos estados hadrônicos num modelo de quarks, uma mudança de representação é implementada de tal maneira que os hádrons sejam descritos por operadores de campo de partículas elementares. A aplicação da transformação unitária ao Hamiltoniano microscópico de quarks dá origem a Hamiltonianos efetivos que descrevem interações quark-quark, hádron-hádron, e hádron-quark. Hamiltonianos bariônicos efetivos foram derivados no contexto de um modelo de quarks constituintes. Em particular, um potencial efetivo NN foi obtido, deslocamentos de fase singletos de spin foram calculados para este potencial e comparados aos deslocamentos de fase gerados pela troca de mésons 'ômega' do potencial de Bonn
Abstract: The field theoretic Fock-Tani formalism, originally developed in atomic physics to deal with systems where the internal degrees of freedom of atoms cannot be neglected, is generalized to composite hadronic systems. Starting from the Fock space representation of hadron bound states in a quark model, a change of representation is implemented by a unitary transformation such that the composite hadrons are redescribed by elementary-particle field operators. Application of the unitary transformation to the microscopic quark Hamiltonian gives rise to effective Hamiltonians that describe quark-quark, hadron-hadron, and quark-quark interactions. Effective baryon Hamiltonians are derived in the context of a constituent quark model. In particular, an efective NN Fock-Tani potential was obtained, spin-singlet phase shifts were calculated for this potential and compared with the ones generated by the 'ômega' exchange of the Bonn potential
Doutor
Katz, Roland. "A quantum approach to dynamical quarkonia suppression in high energy heavy ion collisions." Thesis, Nantes, Ecole des Mines, 2015. http://www.theses.fr/2015EMNA0227/document.
Повний текст джерелаThe theory of quantum chromodynamics (QCD) predicts the existence of a new state of matter: the Quark-GluonPlasma (QGP). The latter may have existed at the first moments of the Universe following the Big Bang and can be, in theory, re-produced under the extreme conditions of temperature and density reached in high energy heavy ion collisions (at the LHC for instance). One of the QGP observables is the suppression of the quarkonia (heavy quark/antiquark bound states), characterised by a smaller production of these states in heavy ion collisions in comparison to proton-protoncollisions, in which no QGP production would be possible. This suppression has indeed been observed experimentally, but the puzzling evolution of its trend from RHIC to LHC energies requires a better theoretical understanding. The present thesis aims at studying the real-time evolution of correlated heavy quark/antiquark pairs described as open quantum systems which permanently interact with a cooling QGP. More explicitly, the continuous interaction between the medium and the pair internal degrees of freedom is obtained through 1) a temperature dependent color screening (“Debye” like) due to color charges in the irvicinity and 2) some fluctuation/dissipation mechanisms reflecting the continuous collisions. It leads to a dynamical and continuous picture of the dissociation, recombination and possible transitions to other bound states. This investigation is at the crossroads of different theoretical frameworks: semi-classic, quantum and quantum fields. The deduced predictions are compared to experimental data and to the results of other theoretical models
Takan, Taylan. "Study Of The Heavy Quarkonia Spectra In The Quark Model." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614102/index.pdf.
Повний текст джерелаIsert, Dagmar Sigrun. "Transport theory for scalar quarks and gluons." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961877200.
Повний текст джерелаWebster, Stephen James. "Improved Monte Carlo simulations of massive quarks." Thesis, Durham University, 2019. http://etheses.dur.ac.uk/12954/.
Повний текст джерелаMartins, Mauro Sebastião. "História das partículas: de elétrons aos quarks." Pontifícia Universidade Católica de São Paulo, 2008. https://tede2.pucsp.br/handle/handle/13384.
Повний текст джерелаThis Work, a thesis in history of subatomic particles, is an historic and epistemological development study of the theoretical and experimental subatomic particles and antiparticles from the early Dirac s quantum theory of the electron, published in a year of 1928, until the publications of the theories of the quarks in a decade of the sixths, the Gell Mann theory of quarks include. That research studies was made in primaries and secondary bibliographies, didactic manuals, articles of scientific journals and scientific magazines, history and philosophy of science books and history of particles books. This studies show that in the delimitated period of study, the paradigmatic theories and experiments appear in the period call of common science, in suite the scientific period is the crisis, so, have a concurrency theories and experimental models period, finally appear a paradigmatic theory and experimental model, like the Khun historical analyses. The paradigmatic particles theories and experimental models, appear a manner of broke up whit of old scientific know, like understood of Bachelard analysis. In the daily period the candidate of paradigmatic theory of particles is the supercordas theory. However, ours studies are conclusive that it have a periodic cycle, into theirs, appear the paradigmatic theoretical and experimental models and had surpassed in the suite period by others paradigmatic theoretical and experimental models, and other periodic cycle occur when of paradigmatic theories and experimental models appear, and so on
Este trabalho, uma tese em história das partículas subatômicas, é um estudo da evolução histórica e epistemológica das teorias e experimentos em partículas e antipartículas, desde o advento da teoria quântica do elétron de Dirac, no ano de 1928, até as publicações das teorias sobre os quarks da década de sessenta, incluindo, nestas, a teoria dos quarks de Gell Mann. Os estudos foram embasados nos levantamentos de bibliografias primárias e secundárias: manuais didáticos, artigos de revistas e jornais científicos, obras em história e filosofia da ciência e em história das partículas. Ele demonstra que o período delimitado para o estudo revela que as teorias e experimentos paradigmáticos surgem após um período de ciência normal, seguido de crise e concorrência entre as teorias e modelos experimentais, como compreendido pela análise histórica de Thomas Khun. As teorias e experimentos paradigmáticos, em partículas, surgem de rupturas com o velho conhecimento estabelecido, como entendido pela análise epistemológica de Bachelard, do desenvolvimento do conhecimento científico. No período atual a candidata à teoria paradigmática em partículas, segundo a manifestação da comunidade científica dos pesquisadores em física de partículas, é a teoria das supercordas. Entretanto, os estudos são conclusivos, quanto à existência de ciclos periódicos, nos quais, as teorias e modelos paradigmáticos aparecem e são superados por outras teorias e modelos paradigmáticos emergentes
Prager, Hugo. "Phenomenology of extra quarks at the LHC." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/424495/.
Повний текст джерелаGIRLANDA, LUCA. "Signature experimentale de la condensation de quarks." Paris 11, 1999. http://www.theses.fr/1999PA112258.
Повний текст джерелаAl, Mamun Md Abdullah. "Nuclei, Nucleons and Quarks in Astrophysical Phenomena." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1563991151449461.
Повний текст джерелаLasry, Nathaniel. "Mélange des quarks : une nouvelle approche géométrique /." Thèse, Montréal : Trois-Rivières : Université du Québec à Montréal, Université du Québec à Trois-Rivières, 2000. http://www.uqtr.ca/biblio/notice/resume/03-2224587R.html.
Повний текст джерелаEn tête du titre: Université du Québec à Montréal. "Mémoire présenté à l'Université du Québec à Trois-Rivières comme exigence partielle de la maîtrise en physique offerte par extension à l'Université du Québec à Montréal en vertu d'un protocole d'entente avec l'Université du Québec à Trois-Rivières". CaQTU CaQTU Bibliogr. : f. 74.
Garcia, André Felipe. "Transição quiral na matéria de quarks magnetizada." Florianópolis, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/100419.
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A física de altas energias é um dos campos de pesquisa mais interessantes da física e de maior atividade atualmente, abrangendo fenômenos físicos que vão desde cosmologia até a física de partículas elementares. Nesta última, sua atuação se dá principalmente nos modernos aceleradores de partículas, como o Relativistic Heavy Ion Collider (RHIC) e o Large Hadron Collider (LHC), onde feixes de partículas colidem entre si produzindo inúmeras outras partículas. A Cromodinâmica Quântica é a teoria que descreve a força nuclear forte entre quarks e glúons, que são os formadores dos hádrons e estão confinados no interior dos mesmos. Entretanto, existe a possibilidade de que em regimes de altas energias caracterizados por temperaturas e/ou densidades elevadas estes quarks e glúons passem da fase hadrônica para uma fase desconfinada representada pelo plasma de quarks e glúons. Essa transição de fase tem inúmeras implicações experimentais (algumas delas sendo atualmente testadas no RHIC e no LHC), além de ser importante na descrição dos estágios iniciais do universo e da matéria que compõe as estrelas de nêutrons. Além disso, recentemente tem-se argumentado que espectadores (partículas periféricas que não se envolvem diretamente na colisão) em colisões não centrais de íons pesados podem gerar fortes campos magnéticos na região de colisão, o que pode influênciar as características da transição de fase. No entanto, devido as dificuldades técnicas em se trabalhar diretamente com a QCD, o uso de modelos efetivos que apresentam algumas propriedades e simetrias desta teoria tem crescido significativamente, mostrando-se uma boa alternativa para contornar estas dificuldades. Um dos modelos mais conhecidos é o modelo de Nambu--Jona-Lasinio (NJL), que, na sua versão mais simples, trata a interação entre quarks up e down como sendo pontual, isto é, sem a participação de gluons. Isto facilita em muito os cálculos envolvidos, apesar de restringir o uso do modelo a escalas de energia que sejam compatíveis com esta aproximação. Nesta dissertação faremos uso da versão SU(2) do modelo de NJL em temperaturas e densidades finitas para estudar a transição quiral na matéria de quarks com e sem a influência de um campo magnético externo. Estudaremos com maiores detalhes o diagrama de fases associado ao modelo, em especial a região da transição de primeira ordem onde há coexistência de fases. Veremos como o campo magnético altera a temperatura pseudo-crítica no crossover, o potencial químico de coexistência em baixas temperaturas e a localização do ponto crítico no diagrama de fases. Até o momento a maioria dos trabalhos relacionados com este tema estão restritos ao estudo dos efeitos do campo magnético no plano $T-\mu$. Neste trabalho damos um passo a frente, investigando também os efeitos do campo magnético sobre algumas grandezas termodinâmicas como a pressão, entropia, densidade bariônica, densidade de energia, susceptibilidade do número de quarks, anomalia do traço e curvas isentrópicas. Um dos resultados mais interessantes da dissertação é uma inesperada "deformação" no diagrama de coexistência de fases no plano $T-\rho$ devido às oscilações na curva de coexistência causadas pelo campo magnético. Este comportamento pode ser entendido em termos do preenchimento dos níveis de Landau em temperaturas baixas.
High energy physics is one of the most interesting research fields of physics in activity nowadays, covering physical phenomena from cosmology to elementary particle physics. Within the latter, high energy physics is present in modern particle accelerators such as the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), where particle beams collide producing several other particles. Quantum Chromodynamics (QCD) is the theory that describes the strong nuclear force among quarks and gluons, which form the hadrons and are confined in their interior. However, there is the possibility that in high energy regimes characterized by high temperatures and/or densities these quarks and gluons undergo a phase transition, changing from the hadronic phase to a deconfined phase represented by the quarkgluon plasma. This phase transition has several experimental implications (some of them being tested in the RHIC and in the LHC), being also important in the description of the early stages of the universe and in the study of the matter in neutron stars. Furthermore, it has been argued in recent years that spectators (particles at the edge of the beam that do not get involved directly in the collision) in non-central heavy ion collision are responsible for creating a strong magnetic field that could affect the features of the phase transitions. However, due to tecnical difficulties in dealing with QCD, the use of less fundamental theories that mimic some of the properties and symmetries of the original theory has growth significantly, being a good alternative to face those difficulties. One of the most popular models is the Nambu{Jona-Lasinio (NJL) model, which, in its simplest version, treats the interaction between up and down quarks as being pontual, with no gluon exchange. This makes calculations a lot easier to perform, but restricts the use of the model to energy scales onsistent with this approximation. In this dissertation we make use of the SU(2) NJL model at finite temperatures and densities in order to study the chiral transition in quark matter under the influence or not of an external magnetic field. We study the phase diagram of the model in detail, paying special attention to the first order transition, where the symmetric and non symmetric phases can coexist. We investigate how the magnetic field affects the crossover pseudocritical temperature, the coexisting chemical potential at low temperatures and the location of the critical end point in the phase diagram. So far, most of the works related to this theme are restricted to the investigation of the magnetic field over the T - u plane only. We take a step forward in this direction, investigating the effects of the magnetic field over some thermodynamic quantities such as the pressure, entropy, baryonic density, energy density, quark number susceptibility, trace anomaly and the isentropic curves or adiabats. One of the most interesting results of this work is the \deformation" of the coexistence phase diagram in the T - u plane caused by the oscillations of the coexistence curve due to the magnetic field. This behavior may be explained in terms of the filing of the Landau levels at low temperatures.
Chan, Ying-kit. "Strange star cooling." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B3138254X.
Повний текст джерелаChan, Ying-kit, and 陳英傑. "Strange star cooling." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B3138254X.
Повний текст джерелаVeiga, J. S. [UNESP]. "Propriedades da matéria nuclear em modelos de quarks constituintes." Universidade Estadual Paulista (UNESP), 1996. http://hdl.handle.net/11449/132865.
Повний текст джерелаLees, Jean-Pierre. "Recherche du quark Top dans l'expérience UA1 par l'étude des événements contenant un électron isolé de grande impulsion transverse accompagné de jets." Chambéry, 1987. http://www.theses.fr/1987CHAMS003.
Повний текст джерелаPeset, Martín Clara. "Effective field theories for heavy quarkonia and hydrogen-like bound states." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/385205.
Повний текст джерелаIn this dissertation, we concentrate on the physics of weakly bound states made of two heavy fermions with different masses. Their description is performed in the framework of effective field theories (EFTs), specifically pNRQED and pNRQCD. We compute the potentials up to next-to-next-to-next-to leading order (N³LO) for two systems: hydrogen-like atoms and heavy quarkonia. We apply our results to the extraction of some associated energy levels. In the first part of this thesis, we obtain a model independent expression for the muonic hydrogen Lamb shift. This expression includes the leading logarithmic terms of order (mα^6 ) as well as the leading hadronic effects of order (mα^5 m²/Λ²). Most remarkably, our analysis include the determination of the spin-dependent and spin-independent structure functions of the forward virtual-photon Compton tensor of the proton to order p³, using HBET and including the Delta particle. Using these results we obtain the leading hadronic contributions to the Wilson coefficients of the lepton-proton four fermion operators in NRQED. The spin-independent coefficient yields a pure prediction for the two-photon exchange contribution to the muonic hydrogen Lamb shift, which is the main source of uncertainty in our computation. The use of EFT crucially helps us organizing the computation, in such a way that we can clearly address the parametric accuracy of our result. Furthermore, we review in the context of NRQED all the contributions to the energy shift of order (α^5), as well as those that scale like (α^6) times logarithms. With our final determination of the Lamb shift, we obtain the proton charge radius in a model independent way. The value we obtain is 6.8σ away from the CODATA value. In the second part of this thesis, we determine the 1/m and 1/m² spin-independent heavy quarkonium potentials in the unequal mass case with order α³ and order α² accuracy, respectively. We discuss in detail different methods to calculate such potentials, and explicitly show the equivalence among them. In particular we obtain, for the first time, the manifestly gauge invariant 1/m and 1/m² potentials in terms of Wilson loops with next-to leading order (NLO) precision. As an application of our results we derive the theoretical expression for the Bc spectrum in the weak-coupling limit to N³LO.
Lapoint, Cary Robert 1970. "Heavy quarkonia production in e⁺ e⁻ collisions at the Z pole." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50420.
Повний текст джерелаRoy, Christelle. "L'Etrangeté du Plasma de Quarks et de Gluons." Habilitation à diriger des recherches, Université de Nantes, 2005. http://tel.archives-ouvertes.fr/tel-00011076.
Повний текст джерелаAprès quasiment 20 ans de recherche auprès des différents accélérateurs de particules américains et européens, le CERN annonce le 10 février 2000 au cours d'une conférence de presse, la mise en évidence expérimentale d'un état particulier de la matière nucléaire, compatible avec la formation d'un QGP, sans pouvoir toutefois le caractériser pleinement. Les expériences du RHIC ont alors pris le relais. Aujourd'hui, au travers une pléthore de résultats nouveaux et parfois bien surprenants, il apparaît de façon de plus en plus certaine, qu'effectivement un état atypique de matière nucléaire a été créé à RHIC et notre vision du QGP comme un gaz parfait de partons n'interagissant que très faiblement, a depuis changé. Un nouvel acronyme a été défini : sQGP pour Strongly Interacting QGP.
Pour parvenir à cette observation, il a fallu passer par la caractérisation même de l'évolution des collisions d'ions lourds, du point de vue chimique et dynamique, en comparant les phénomènes des collisions d'ions lourds pour lesquelles les conditions devraient être réunies pour former un QGP à des collisions d'énergies moindres ou de systèmes plus légers qui ne peuvent permettre cette formation. Le QGP est en effet produit de manière beaucoup trop furtive pour pouvoir le sonder directement. Mon mémoire d'Habilitation à Diriger des Recherches présente les résultats des analyses que j'ai menées et qui ont contribué à la mise en évidence de la formation d'un état nouveau au RHIC et à cette nouvelle vision du plasma. Les stigmates du QGP ont été recherchés avec les particules contenant des quarks étranges : les résonances de particules simplement étranges et les baryons doublement étranges.
La production des résonances étranges Lambda(1520) apporte en effet des informations sur la phase d'hadronisation du plasma (lorsque les partons se recomposent en hadrons) : selon leur observation ou non, il pourrait être possible de caractériser le freeze-out chimique (instant où les interactions inélastiques cessent et la composition chimique du système est figée), le freeze-out cinétique (instant où les interactions élastiques cessent et les particules n'interagissent plus), si ces deux freeze-out coïncident ou si, au contraire ils sont séparés dans le temps et de combien. L'idée est la suivante : les Lambdas(1520) se désintègrent quasiment instantanément en un proton et un kaon. Par conséquent, si le temps entre les freeze-out chimique et cinétique est long, les produits de désintégration de ces particules peuvent être absorbés dans le milieu dense qui a été créé. En revanche, si les deux freeze-out coïncident ou sont très proches, les produits de désintégration ne sont pas affectés et la particule mère, c'est-à-dire la résonance, peut être identifiée. Ainsi, en mesurant les taux de production de ces particules dans les collisions proton–proton pour lesquelles les deux freeze-out coïncident, et en comparant les taux obtenus dans les collisions Au–Au, à l'énergie nominale du RHIC, il est apparu qu'effectivement, au moins 4 fm/c séparent les deux freeze-out dans les collisions Au–Au. Cette conclusion constitue une étape importante dans la compréhension des collisions d'ions lourds ultra-relativistes et du comportement de la matière dans des conditions extrêmes. Cette analyse est apparue comme originale au sein de la collaboration STAR, étant la première étude sur les résonances étranges. Des algorithmes spécifiques ont dû être mis au point et sont largement utilisés au sein de la collaboration qui depuis étudie de nombreuses autres résonances ou recherche des objets plus exotiques.
La production des baryons étranges a été largement investiguée les années passées car une augmentation « anormale » des taux de production est attendue si un QGP est formé. Les expériences du CERN ont observé effectivement une surproduction de l'étrangeté dans les collisions Pb–Pb mais n'ont pu conclure de manière décisive quant à une formation éventuelle d'un plasma car ces résultats pouvaient être également reproduits par des modèles de gaz de hadrons. Nous avons mené une analyse similaire avec les données de STAR en comparant les taux de production des Xi, baryons doublement étranges, dans les collisions proton–proton et Au–Au à sqrt(s_NN) = 200 GeV. Là aussi, les résultats sont demeurés ambigus. Ainsi, ces résultats ont conduit un certain nombre de physiciens à ne plus considérer les taux de production de particules étranges comme une signature robuste de la formation d'un QGP. En revanche, l'étrangeté est revenue sur le devant de la scène, de façon plus indirecte donnant des informations très diverses et sur les différentes étapes de la collision.
Les Xi ont révélé tout d'abord que le système créé à l'énergie nominale du RHIC serait en équilibre thermique et chimique et que les températures de freeze-out chimique sont proches de la température de déconfinement prédite par QCD. Nous avons également étudié les phénomènes dynamiques collectifs, appelés flot, qui naissent des interactions entre constituants et se traduisent par une émission de matière dans des directions privilégiées de l'espace de phase. En accord avec leurs faibles sections efficaces d'interaction, les Xi semblent émis bien plus tôt que les particules plus légères. Toutefois, le fait que ces baryons subissent un flot important, laisse supposer qu'elles auraient développé un flot, donc qu'elles auraient été soumises à des interactions, avant la phase d'hadronisation, autrement dit, dans une phase partonique. Les partons subiraient donc des interactions résiduelles, contrairement à ce que préconisaient les théoriciens du milieu des années soixante-dix.
Par ailleurs, en 2003, les quatre expériences du RHIC ont révélé conjointement la mise en évidence du phénomène de jet-quenching dans les collisions d'ions lourds : il traduit une diminution de la production de particules chargées de très haute impulsion transverse s'expliquant par la perte d'énergie des partons dans un milieu très dense. Nous avons réalisé cette analyse en considérant les X et montré que non seulement ces baryons subissent un jet-quenching mais aussi qu'ils ont un comportement différent de celui des mésons. Une dépendance des phénomènes dynamiques au type de particules a ainsi été mise en évidence en accord avec les modèles de coalescence préconisant que les hadrons se forment à partir de la recombinaison des quarks. Là aussi, émergence des partons comme degrés de liberté pertinents.
A partir de ces résultats entre autres, certains théoriciens affirment la découverte du QGP à RHIC mais les expérimentateurs sont plus prudents et désirent auparavant confirmer et enrichir leurs résultats par l'étude d'autres observables qui viendraient corroborer ces observations. Ces années ont été particulièrement stimulantes par l'évolution de nos connaissances grâce aux formidables résultats produits par les quatre expériences du RHIC. Les « vielles » signatures ont fait peau neuve se transformant en sondes nouvelles et riches en informations originales. La conception du QGP a évolué : il ne s'agit plus d'un gaz parfait constitué de partons évoluant librement mais d'un sQGP.
Perret, Pascal. "Tests électrofaibles du Modèle Standard et quarks lourds." Habilitation à diriger des recherches, Université Blaise Pascal - Clermont-Ferrand II, 2002. http://tel.archives-ouvertes.fr/tel-00001683.
Повний текст джерелаAndrieux, Vincent. "Polarisation of quarks and gluons inside the nucleon." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112244/document.
Повний текст джерелаThe work presented in this thesis is related to the study of the longitudinal spin structure of the nucleon. The aim is to determine the contribution to the spin 1/2 of the proton in terms of its constituents, quarks and gluons. The analysis is performed on the data taken with the COMPASS experiment, which benefits from a polarised muon beam at 200 GeV scattered off polarised protons from an ammonia target of 1.2 m long. The double longitudinal spin asymmetry of deep inelastic scattering cross-Section. The spin-Dependent structure function of the proton g₁p is derived from these measurements, which extend the kinematic world coverage to unexplored region so far (0,0036 < x< 0,57; 1,03 < Q² (GeV/c)² < 96 and 23 < W² (GeV/c)² < 320).The results obtained with a high statistical precision are included in a Next-To-Leading order QCD analysis of world g₁p, g₁d and g₁n (proton, deuteron and neutron) data to parametrise the polarised quark and gluon distributions. The g₁ world coverage of the x and Q² kinematic domain, which is a key point in the sensitivity to the gluon polarisation ΔG, turns out to be too limited for an accurate ΔG determination. Nevertheless, the QCD analysis allows to determine the quark spin contributions to the proton spin to 0.26<ΔΣ<0.33 at Q² = 3 (GeV/c)² in the MSbar scheme. The dominant uncertainty on ΔΣ is related to the choice of functional forms assumed in the fit. Finally, the Bjorken sum rule, which constitutes a fundamental test of QCD, is verified on the COMPASS data alone with a precision of 9%
Mello, Cedrick Miranda. "Estudo da detecção de quarks top no LHC." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-08032013-122617/.
Повний текст джерелаThis study was to examine the possibility of verifying the violation of flavor in neutral currents mediated by Kaluza-Klein gluons (GKK), in which it was introduced by compact warped extra dimensions. The possibility of violation of flavors in neutral currents occurs through processes like proton/proton into quark top/ antiquark charm. Initially we studied the behavior of jets with high transverse momentum (the order of 300 GeV) and its substructures. After this, we studied the detection of the top quark via HEPTopTagger and Johns Hopkins algorithms (we did a brief comparison between them). Finally, we proposed two ways to find the GKK. One of them, by searching for only quark top. The other, by looking for a quark top and a jet without substructure (algorithm of TJ type). We could see that the possibility of encountering the phenomenon of violation of flavors is accessible (the ratio S/B is the order of 0.1) in both cases of mass analyzed by TJ type algorithm.
Motta, Théo Ferraz. "Matéria de Quarks fria sob campo magnético forte." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-25052017-105222/.
Повний текст джерелаThis dissertation presents a brief introductory overview of some key aspects of nuclear astrophysics and of the phenomenology of the quark gluon plasma at cold temperatures which is believed to exist inside the core of neutron stars and possible other compact astrophysical objects. An equation of state for this state of matter is derived incluing the influence of gluon condensates and the magnetic field which is also an important characteristic of neutron stars. And finally this equation of state is applied to the study of compact stellar structure and some important results are discussed.
Carvalho, Sheyse Martins de. "Efeitos do confinamento na matéria de quarks supercondutora." Instituto Tecnológico de Aeronáutica, 2010. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1564.
Повний текст джерелаTran, Huong Lan. "Recherche de quarks lourds avec le détecteur ATLAS." Paris 7, 2013. http://www.theses.fr/2013PA077274.
Повний текст джерелаA search for heavy quarks is presented in this thesis. It is organized in three main parts. In the first part presented the study on the quality factor for the liquid Argon calorimeters of ATLAS. The Q-factor is a quantity defined to estimate the agreement between the measured and the predicted pulse shape. In case the prediction is not perfect, it can lead to spurious rejection of good signal. The prediction however can be corrected using a pure sample of signal selected from the data. The results show a clear improvement: correcting the prediction helped to reduce the dependence of the Q-factor on the signal's energy. The new pulse shape predictions have been stored in the ATLAS database to be used in the next data reprocessing. The second part is the heart of the thesis: development of a novel analysis to search for heavy quarks. This novel approach is performed in three steps. In the first step, a Likelihood fit method is built to determine the number of signal events in the data. An excess w. R. T. Expectation in absence of signal events is observed: N = 82+39. In the second step, the Plot method is used to reconstruct distributions S-36 s of control variables, for instance the invariant mass of three jets. The result shows distributions compatible with the null hypothesis. Finally in the last step, a statistical method has been developed to combine the output of the first two steps. The method leads to a result compatible with the standard approach in ATLAS; It excludes heavy quarks with masses mtbelow 520 GeV/c2 (600 GeV/c2 expected) at 95 % CL using 4. 7 fb-i of 7 TeV data. The last part of this thesis presents my contribution to the Exotics Group on the search for vector-like quarks, where I was involved in the same-sign dilepton channel analysis; I also contributed to the combination of various analyses. As a summary, a vector-like quark of charge +2/3 (-1/3) with mass smaller than 550 (450) GeV/c2 is excluded regardless of its branching ratio to tH, tZ or bW (bH,bZ,tW )
Khamseh, Ava. "Lattice phenomenology of heavy quarks using dynamical fermions." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28855.
Повний текст джерелаMedina, Tulio Eduardo Restrepo. "Geração radiativa de repulsão vetorial para quarks leves." reponame:Repositório Institucional da UFSC, 2014. https://repositorio.ufsc.br/xmlui/handle/123456789/129306.
Повний текст джерелаMade available in DSpace on 2015-02-05T20:56:09Z (GMT). No. of bitstreams: 1 330269.pdf: 2723044 bytes, checksum: acc5bb1f16ab0d07a08b676e16f1ea63 (MD5) Previous issue date: 2014
Abstract: We apply a non-perturbative analytical method, known as the Optimized PerturbationTheory (OPT), to the Polyakov-Nambu-Jona-Lasinio (PNJL) model in order to investigate physical quantities associated with the QCD phase transitions. We consider the Taylor expansion of the pressure in powers of µ/T obtaining the second cumulant (c2) which is associated to the quark number susceptibility. We discuss how the OPT nite Nc radiative (quantum) corrections induce a contribution to the pressure which behaves as a vector repulsion even when such a channel is absent in the original classical potential. Our results are then compared with the ones furnished by lattice QCD simulations and by the large-Nc approximation showing that, physically, the OPT results resemble those furnished by the latter approximation when a repulsive vector channel is explicitly included in the classical potential. In this case, both approximations fail to correctly describe the Stefan-Boltzmann limit at high temperatures. We discuss how this problem can be circumvented by taking the couplings to be temperature dependent so as to simulate the phenomenon of asymptotic freedom. Since this is the first time the OPT is applied to the PNJL we also discuss many technicalities associated with the evaluation of two loop (exchange) diagrams.
Neste trabalho o método analítico não perturbativo conhecido como Teoria de Perturbação Otimizada (OPT) é aplicada ao modelo de Polyakov-Nambu-Jona-Lasinio (PNJL) para que quantidades físicas, associadas com as transições de fase da QCD, possam ser calculadas. A expansão da pressão em potências de µ/T é considerada para obter o segundo cumulante (c2) que é uma quantidade relacionada com a susceptibilidade do número de quarks. Primeiramente discutimos como as correções radiativas de Nc finito geradas pela OPT produzem uma contribuição que se comporta como um termo vetorial repulsivo mesmo quando este tipo de canal está ausente no potencial clássico original. Em seguida, nossos resultados são comparados com aqueles fornecidos pelas simulações na rede e também pela aproximação de Nc grande(LN). Fisicamente, os resultados da OPT são similares aqueles fornecidos pela aproximação LN quando um canal vetorial repulsivo é explicitamente incluido no potencial clássico. Neste caso, nenhuma destas aproximações analíticas produz corretamente o limite de Stefan Boltzmann para altas temperaturas. Contudo, nossos resultados sugerem como estes problemas podem ser contornados tomando-se as constantes de acoplamento como sendo dependentes da temperatura, de maneira que o fenômeno da liberdade assimptótica possa ser simulado. Esta é a primeira vez que a OPT é aplicada ao modelo de PNJL e por isto vários aspectos técnicos relacionados com o cálculo de diagramas de dois laços são também aqui apresentados.
Bousson, Nicolas. "Recherche de nouveaux quarks lourds avec l'expérience ATLAS au LHC. Mise en oeuvre d'algorithmes d'identification de jets issus de quarks b." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4101/document.
Повний текст джерелаThe hypothesis of a fourth generation of fermions – the matter particles described in the Standard Model (SM) of particle physics – is one of the simplest model of new physics still not excluded and accessible at the start of the Large Hadron Collider (LHC) – the world most powerful hadron collider since 2009. We search for the pair production of up-type t' quarks decaying to a W boson and a b-quark. The search is optimized for the high quark mass regime, for which the production can be distinguished from the top background by exploiting kinematic features of the decay products arising from the proton-proton collisions occurring at the center of the ATLAS detector. We present a novel search strategy reconstructing explicitly very high-pT W bosons from their collimated decay products. The analysis benefits from the commissioning of algorithms intended to identify jets stemming from the fragmentation of b-quarks. These algorithms are based on the precise reconstruction of the trajectory of charged particles, vertices of primary interaction and secondary vertices in jets. The b-tagging ability allows for ATLAS to improve the (re)discovery of the SM, and the sensibility to new physics. It will hence play an important role in the future of the LHC, the reason why we study the expected performance with an upgrade of the ATLAS pixel detector, called IBL and currently under construction. Our search of t' quark, using 4.7 fb^−1 of the 7 TeV data collected in 2011, has resulted in the world most stringent limit, excluding t' masses below 656 GeV, with also an interpretation in the framework of vector-like quarks
Gimenez, Diógenes Domenicis. "Estudo da coincidência elétron-jato em colisões próton-próton e próton-núcleo no experimento ALICE." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-13032018-134433/.
Повний текст джерелаThis thesis presents the first measurement of the distribution of jets that are correlated to heavy-flavour decay electron (HFe), reconstructed and identified with ALICE (A Large Ion Collider Experiment). The observables were measured in pp collisions at center of mass energy s = 8 TeV and in p-Pb at sNN = 5.02 TeV at the Large Hadron Collider (LHC). Exploring the heavy quarks created in relativistic heavy ion collisions is a powerful approach to study the new formed medium, known as Quark Gluon Plasma (QGP). This is due to the fact that they are created in the beginning of the collision, via hard scattering, and interact with the QGP throughout its whole existence. These quarks fragment into mesons that can decay (via the semi-electronic channel) into electrons (and positrons). These leptons can be used to identify the creation of a heavy quarks and allow QGP studies. The hard scattering, fragmenting and decaying processes originate several particles that are collimated in a conical region, and they can be grouped in what is called jet. The reconstruction and study of jets has been used to retrieve more information about the QGP and it is also a useful probe. The selected electrons were identified by the Time Projection Chamber (TPC) and the Electromagnetic Calorimeter (EMCal). Heavy-flavour decay electrons were selected via invariant mass method. The jets were reconstructed by the Fastjet framework, with the algorithm anti kT and R = 0.4. The HFe-jet pairs selection may allow a better comprehension of the QGP properties and its interactions with the heavy quarks. A jet pT,chjet spectrum was obtained, for pp and p-Pb, in two intervals of angular distance between the jet and the electron: away and near sides. The angular distance distribution was also obtained in different electron peT intervals. The results for pp and p-Pb were compared through two observables: the first one as a function of the jet pT,chjet, and the second, as a function of electron peT. The former consists in calculating the ratio of the jet pT,chjet spectra, in pp and in p-Pb. The latter, consists in calculating the ratio of the areas, in pp and in p-Pb, of each peak in the distribution. Both were compatible with the unity, which indicates that there is no extra effect in p-Pb with respect to pp.
Harko, Tiberiu. "Properties of strange stars." Thesis, Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23242280.
Повний текст джерелаBoudinov, Edouard. "Measurement of the strange quark forward-backward asymmetry around the Z0 peak." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/83185.
Повний текст джерела