Quantum Chromodynamics
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Lattice QCD: a nonperturbative study in the Feynman Gauge / QCD na rede: um estudo não-perturbativo no calibre de Feynman
The infrared behavior of gluon and ghost propagators is of fundamental importance for the understanding of the low-energy limit of quantum chromodynamics (QCD), especially with respect to the problem of the confinement of quarks and gluons. The goal of this thesis is to implement a new method to study the gluon propagator in the linear covariant gauge in lat
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/08/2011
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2. Transições de fase hádron-quark em estrelas de nêutrons
Recent advances on the field of high energy physics have enabled the study of matter under extreme conditions and, in this context, new states of matter are being discovered and speculated upon. Among these hypothetical states of matter is the one of deconfined quarks in high densities and/or temperatures. An environment with extreme densities and low temper
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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3. Efeitos nucleares no processo Drell-Yan : formalismos de dipolos de cor e de momentum transversal intrínseco
O principal tema desenvolvido nesta tese é o estudo de efeitos nucleares na produção de diléptons por meio do processo Drell–Yan para energias compatíveis com as de RHIC e de LHC. Dois modelos são usados: o formalismo de dipolos de cor e o modelo de pártons com momentum transversal intrínseco. No primeiro capítulo, uma breve introdução históric
Publicado em: 2010
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4. Study of the structure of new mesons / Estudo da estrutura dos novos mésons
We use QCD sum rules to test the nature of the recently observed mesons Y (4260), Y (4360) and Y (4660), assumed to be exotic four-quark (c¯cq¯q) or (c¯cs¯s) states with JPC = 1. We work at leading order in s, consider the contributions of higher dimension condensates and keep terms which are linear in the strange quark mass ms. We find for the (c¯cs¯s
Publicado em: 2009
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5. Charm production in neutral current neutrino-nucleus scattering within the color dipole approach
The rate for inclusive charm production in neutral current neutrino-nucleus interactions is calculated. The interaction of high energy neutrinos on hadron targets is an outstanding probe to test Quantum Chromodynamics (QCD) and shed light in the understanding of the parton properties of hadron structure. We have considered the QCD color dipole picture for su
Brazilian Journal of Physics. Publicado em: 2008-09
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6. Espectro de excitação para modelos de teorias quânticas de campo na rede: modelos puramente fermiônicos e modelos de cromodinâmica quântica / Excitation spectrum for quantum field theory models on the lattice: pure fermionic models and quantum chromodynamics models
In this thesis, we obtain, from a mathematically rigorous point of view, the low-lying energy-momentum spectrum of two $3+1$ dimensional imaginary time lattice quantum filed theory with fermion fields (we give explicit results for the case $d = 3$ and Dirac matrices): a pure fermionic model with quartic interaction in the $N$-component fermion field and a qu
Publicado em: 2008
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7. Dynamical gluon mass in QCD processes
We perform phenomenological applications of modified gluon propagators and running coupling constants in scattering processes in Quantum Chromodynamics (QCD). The modified forms of propagators and running coupling constant are obtained by non-perturbative methods. The processes investigated includes the diffractive ones - proton-proton elastic scattering, li
Brazilian Journal of Physics. Publicado em: 2007-07
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8. Gluon dominance model and cluster production
Multiparticle production in lepton and hadron processes is studied by means of the Gluon Dominance Model (GDM) which is based on the Quantum Chromodynamics (QCD) and phenomenological scheme of hadronization. The model describes the multiplicity distributions and their moments very well. It has revealed an active role of gluons in multiparticle production and
Braz. J. Phys.. Publicado em: 2007-06
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9. Aspectos não perturbativos das teorias de Yang-Mills. / Non-perturbative aspects of Yang-Mills theory
Alguns aspectos não perturbativos das teorias de Yang-Mills puras em quatro dimensões Euclideanas, quantizadas no calibre de Landau, são estudados analiticamente. Por pura entendemos a teoria na ausência de matéria (férmions). Em particular, ivestigamos a geração dinâmica de massa para os gluons devido a presença de condensados de dimensão dois. E
Publicado em: 2007
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10. A QCD inspired model for proton-proton and antiproton-proton scatterings / Espalhamento difrativo de hadrons : desenvolvimento de um modelo baseado na QCD e determinação de limites extremos de parametros do pomeron
Não informado
Publicado em: 2005
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11. QCD at high parton density
The high parton density regime of Quantum Chromodynamics (QCD) is briefly discussed. Some phenomenological aspects of saturation are described, mainly focusing on possible signatures of the non-linear QCD dynamics in electron-proton/nucleus collisions. Implications of these effects in central and ultraperipheral heavy-ion collisions are also presented.
Brazilian Journal of Physics. Publicado em: 2004-12
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12. Percolation of Monte Carlo clusters
Percolation theory is of interest in problems of phase transitions in condensed matter physics, and in biology and chemistry. More recently, concepts of percolation theory have been invoked in studies of color deconfinement at high temperatures in Quantum Chromodynamics. In the present paper we briefly review the basic concept of percolation theory, exemplif
Brazilian Journal of Physics. Publicado em: 2004-03