Gev 1
Mostrando 25-36 de 42 artigos, teses e dissertações.
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25. X (3872) in QCD sum rules
QCD spectral sum rules is used to test the nature of the meson X(3872), assumed to be an exotic four-quark $(c\bar{c}q\bar{q})$ state with J PC = 1++. For definiteness, the current proposed recently by Maiani et al [1] is used, at leading order in alphas, considering the contributions of higher dimension condensates. The value M X = (3.94±0.11) GeV is found
Brazilian Journal of Physics. Publicado em: 2007-03
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26. STUDY OF HEAVY VECTOR MESONS AT PHENIX DETECTOR. / Estudos de mésons vetoriais pesados no detector Phenix
Neste trabalho são reportadas medidas realizadas no detector PHENIX do RHIC sobre J/Psi em colisões p+p e Au+Au a s^(1/2) = 200 GeV na região de rapidez central e Psiem colisões p+p nas mesmas condições. As medidas incluem a dependência com o momento transverso da produção de charmônio e o fator de modificação nuclear de J/Psis para vários regim
Publicado em: 2007
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27. DeterminaÃÃo do Ãndice de disponibilidade de umidade para a RegiÃo Oeste do ParanÃ
O presente trabalho teve como objetivo comparar os modelos de estimativa de EvapotranspiraÃÃo de ReferÃncia (ETo) Gama, Lognormal, e o modelo de distribuiÃÃo generalizada de valores extremos (GEV), calculada atravÃs do modelo de Camargo, na regiÃo Oeste do Paranà e determinar o Ãndice de Disponibilidade de Umidade â IDU. Os dados climÃticos foram
Publicado em: 2006
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28. Um estudo hidrodinâmico do fluxo elíptico em colisões nucleares relativísticas / A hydrodynamic study of the elliptic flow in relativistic nuclear collisions
Nesta dissertação calculamos o parâmetro de fluxo elíptico v2, em função da pseudorapidez η, do momento transversal pt e da centralidade da colisão. Encontramos que v2, em função de η, reproduz a forma característica dos dados experimentais, apresentando um máximo em η = 0 e diminuindo conforme |η| aumenta. Obtivemos, também,
Publicado em: 2006
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29. Photofissility at 1 GeV for nuclei throughout the periodic table
A new approach to evaluate nuclear photofissilities at incident photon energies above the pion photoproduction threshold has been recently developed and proved to describe successfully the fissilities of natPb and 232Th target nuclei at energies ~0.2-4.0 GeV. The method is merely a simple, semiempirical description of the photofission reactions in which fiss
Brazilian Journal of Physics. Publicado em: 2005-09
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30. Spallation physics and the ADS target design
This paper reviews the physics of the spallation which is a nuclear reaction in which a particle (e.g. proton) interacts with a nucleus. Given to the high energy of the incident proton, in a first stage it interacts with the individual nucleons in an intranuclear cascade which leads to the emission of secondary particles (neutrons, protons, mesons, etc.). In
Brazilian Journal of Physics. Publicado em: 2005-09
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31. Evaluation of the fluence to dose conversion coefficients for high energy neutrons using a voxel phantom coupled with the GEANT4 code
Crews working on present-day jet aircraft are a large occupationally exposed group with a relatively high average effective dose from galactic cosmic radiation. Crews of future high-speed commercial flying at higher altitudes would be even more exposed. To help reduce the significant uncertainties in calculations of such exposures, the male adult voxels phan
Brazilian Journal of Physics. Publicado em: 2005-09
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32. AnÃlise de dados do detector de ondas gravitacionais Allegro: verificaÃÃo de assinaturas de sistemas de mini-buracos negros.
Neste trabalho construÃmos um filtro digital do tipo "matched dois modos" para verificarmos assinaturas de um sinal impulsivo, de radiaÃÃo gravitacional, emitido por um sistema de mini-buracos negros de 0,5 massa solar pouco antes de sua coalescÃncia. Para determinar a forma de onda irradiada pelo sistema, foram utilizadas as equaÃÃes de campo da Teori
Publicado em: 2005
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33. The electromagnetic properties of the light pseudoscalar mesons via the Primakoff effect
The PrimEx (Primakoff Experiment) Collaboration is currently preparing to perform a high precision (1.4%) measurement of the two photon decay width of the neutral pion, . The proposed 12 GeV upgrade of the CEBAF accelerator will enable a significant enlarging of the
Brazilian Journal of Physics. Publicado em: 2004-09
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34. Developement of crisp package for spallation reaction studies and its utilization in ADS (Accelerator Driven System)
The progress of nuclear physics had allowed a better understanding of nuclear structure and reaction mechanisms, but also enables important applications of nuclear energy in our modern way of life. We can point out those ones related to power generation from nuclear reactors, providing an almost inexhaustive power source due to the huge quantities of nuclear
Brazilian Journal of Physics. Publicado em: 2004-09
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35. Vector meson and associated strangeness production using a linearly polarized photon beam at Jefferson lab
The set of experiments forming the g8a run took place in the summer of 2001 in Hall B of Jefferson Lab. The g8a run was the commissioning experiment for the linearly-polarized photon beam at CLAS. The aim of these experiments is to improve the understanding of the underlying symmetry of the quark degrees of freedom in the nucleon, the nature of the parity ex
Brazilian Journal of Physics. Publicado em: 2004-09
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36. A model for J/psi - kaon cross section
We calculate the cross section for the dissociation of J/psi by kaons within the framework of a meson exchange model. We find that, depending on the values of the coupling constants used, the cross section can vary from 5 mb to 30 mb at ~ 5 GeV.
Brazilian Journal of Physics. Publicado em: 2004-03