Quarks
Mostrando 25-36 de 90 artigos, teses e dissertações.
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25. História das partículas: de elétrons aos quarks
This 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 Diracs 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 t
Publicado em: 2008
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26. AplicaÃÃes de mÃtodos de quÃmica quÃntica: adsorÃÃo de H2 em Pd e um modelo para nucleons
A QuÃmica QuÃntica tem oferecido marcantes e variadas contribuiÃÃes na descriÃÃo e previsÃo de inÃmeros fenÃmenos da natureza. Referendando tal potencialidade, utilizamos neste trabalho os mÃtodos de quÃmica quÃntica para abordar dois temas bastante distintos: adsorÃÃo de H2 em Pd e a descriÃÃo de nucleons atravÃs de um modelo molecular. Bas
Publicado em: 2008
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27. Produção de estranheza em colisões de ions pesados relativisticos / Strangeness production in relkativistic heavy ion collisions
Relativistic heavy-ion collisions allow us to study the behavior of nuclear matter at extreme conditions of temperature and energy density. In these conditions, we expect a phase transition of matter where a free state of quarks and gluons would be formed, and that is known as Quark-Gluon Plasma (QGP). With the aim to study this new state of matter and its f
Publicado em: 2008
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28. Quark matter (strangelets) from astrophysical sources and its detection by terrestrial experiments. / Matéria de quarks (strangelets) de origem astrofísica e sua detecção por experimentos terrestres
The strange quark matter hypothesis, which states that a plasma composed of quarks up, down and strange in roughly equal amounts is absolutely stable at zero pressure, has been studied for more than twenty years, both theoretically and during searches for its detection in specific experiments. If strange quark matter is indeed stable, then there could be imp
Publicado em: 2008
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29. Produção e propagação de pártons energéticos no meio nuclear
A descoberta da atenuação de jatos em colisões Au+- Au centrais no Colisor Relativístico de Íons Pesados (RHIC) no Laboratório Nacional de Brookhaven fornece evidências claras da formação de matéria densa fortemente interagente. Esta atenuação foi prevista para ocorrer devido à perda de energia de pártons de alta energia que se propagam atravé
Publicado em: 2008
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30. J/psi and Upsilon measurements in p+p collisions at sqrt{s}=200 GeV in the STAR experiment / Medidas de J/psi e Upsilon em colisões p+p a raiz{s} =200 GeV no experimento STAR
Neste trabalho obteve-se, com o experimento STAR, medidas de produção de J/ψ e ϒ em rapidez central (η=0), em colisões p+p com √s = 200 GeV no RHIC. A medida de ϒ foi a primeira medida de bottomonium em rapidez central no RHIC. Essas medidas servem como linha de base para a investigação experimental sistemática da supressão d
Publicado em: 2008
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31. Extending SUSY reach at the CERN large hadron collider using b-tagging
We analyze the potential of the CERN Large Hadron Collider on the reach of the focus point (FP) region in the mSUGRA parameter space. This region, consistent with WMAP results, is characterized by multi-TeV masses for the superpartners of quarks and leptons and relatively light charginos and neutralinos. Moreover, since the LSP has a substantial higgsino com
Brazilian Journal of Physics. Publicado em: 2007-07
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32. Photon-hadron interactions in pA/AA collisions and the QCD dynamics
In this contribution we study the photoproduction of heavy quarks in coherent proton-nucleus (pA) and nucleus-nucleus (AA) interactions for RHIC and LHC energies and analyze if this process can be used to determine the QCD dynamics at high energies. The integrated cross section and rapidity distribution are estimated. Our results indicate that the nonlinear
Brazilian Journal of Physics. Publicado em: 2007-07
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33. On the Faddeev-Popov operator eigenspectrum in topological background fields
During the last years significant progress has been made in the understanding of the confinement of quarks and gluons. However, this progress has been made in two directions, which are at first sight very different. On the one hand, topological configurations seem to play an important role in the formation of the static quark-anti-quark potential. On the oth
Brazilian Journal of Physics. Publicado em: 2007-07
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34. Elastic energy loss in an expanding QGP
The discovery of the jet quenching in central Au + Au collisions at the Relativistic Heavy-ion Collider (RHIC) has provided clear evidence for the formation of strongly interacting dense matter. It has been predicted to occur due to the energy loss of high energy partons that propagate through the quark gluon plasma. Since the medium is not static and it coo
Brazilian Journal of Physics. Publicado em: 2007-07
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35. Heavy flavour production in ep collisions at HERA
Heavy flavour quarks in ep collisions are produced mostly from pair-production through a fusion of a virtual photon and a gluon from the proton. Therefore, the production cross sections provide information on the gluon distribution in the proton. The presence of a hard scale from the heavy quark mass, in principle, ensures that the cross sections are calcula
Braz. J. Phys.. Publicado em: 2007-06
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36. Heavy flavor measurements at RHIC
The study of heavy flavor production in relativistic heavy ion collisions is an extreme experimental challenge but provides important information on the properties of the Quark-Gluon Plasma (QGP) created in Au+Au collisions at RHIC. Heavy quarks are believed to be produced in the initial stages of the collision, and are essential on the understanding of part
Braz. J. Phys.. Publicado em: 2007-06