Qcd Model
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. 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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2. On the inverse problem in high-energy elastic hadron scattering and the applicability of a representation for the real part of the amplitude / Um estudo sobre o problema inverso do espalhamento elastico de hadrons em altas energias e a aplicabilidade de uma representacao para a parte real da amplitude
The theoretical description of high-energy elastic hadron scattering constitutes an open problem in both, the underlying quantum field theory of strong interactions (QCD) and the phenomenological context. In this work the inverse problem in elastic hadron scattering is discussed in the impact parameter and eikonal frameworks, specifically a study on the empi
Publicado em: 2010
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3. Inverse problem in proton-proton elastic scattering in the impact parameter representations / Problema inverso do espalhamento elastico proton-proton na representacao de parametro de impacto
The Impact Parameter and Eikonal Representations are investigated by means of an empirical analysis of the experimental data on proton-proton elastic scattering, at the highest energy region with experimental information available (six data sets at center of mass energies 19.4 - 62.5 GeV). Making use of a novel model-independent parametrization for the scatt
Publicado em: 2009
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4. Photoproduction of excited baryons in the 1 /Nc expansion of QCD
We present results for the photoproduction helicity amplitudes of excited baryons obtained in the context of the 1 /Nc expansion of QCD. The results show that, in order to get a satisfactory description of the observed photoproduction amplitudes, the sub-leading corrections in 1/Nc are important. We also find that, while one-body effective operators are domi
Brazilian Journal of Physics. Publicado em: 2008-09
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5. Forward Physics at the LHC: within and beyond the Standard Model
We review the detection capabilities in the forward direction of the various LHC experiments together with the associated physics programme. A selection of measurements accessible with near-beam instrumentation in various sectors (and extensions) of the Standard Model (SM) is outlined, including QCD (diffractive and elastic scattering, low-x parton dynamics,
Brazilian Journal of Physics. Publicado em: 2008-09
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6. Investigating gluino production at the LHC
Gluinos are expected to be one of the most massive sparticles (supersymmetric partners of usual particles) which constitute the Minimal Supersymmetric Standard Model (MSSM). The gluinos are the partners of the gluons and they are color octet fermions, due this fact they can not mix with the other particles. Therefore in several scenarios, given at SPS conven
Brazilian Journal of Physics. Publicado em: 2008-09
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7. Dipole scattering amplitude in momentum space: investigating fluctuations at HERA
We extend a recently proposed dipole model which relates the virtual photon-proton cross section to the dipole-proton forward scattering amplitude in momentum space investigating the effects of the gluon number fluctuations. The model interpolates between well known asymptotic behaviours predicted by perturbative QCD from the Balitsky-Kovchegov equation, whi
Brazilian Journal of Physics. Publicado em: 2008-09
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8. 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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9. Anomalous diffusion of pions at RHIC
After pointing out the difference between normal and anomalous diffusion, we consider a hadron resonance cascade (HRC) model simulation for particle emission at RHIC and point out that rescattering in an expanding hadron resonance gas leads to a heavy tail in the source distribution. The results are compared to recent PHENIX measurements of the tail of the p
Brazilian Journal of Physics. Publicado em: 2007-09
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10. Deeply virtual compton scattering in color dipole formalism
In this contribution we summarize recent investigations on the deeply virtual Compton Scattering (DVCS) within the color dipole approach. The color dipole cross section is implemented through the phenomenological saturation model. The role played by its QCD evolution and skewedness effects in the DVCS cross section are discussed. The results are compared wit
Brazilian Journal of Physics. Publicado em: 2007-07
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11. Phase diagram of quark matter in nonlocal chiral models under color and electric charge neutrality conditions
We consider the phase diagram of two-flavor quark matter under neutron star constraints for the case of two nonlocal, covariant quark models within the mean field approximation. In one of these models (Model I) the nonlocality arises from the regularization procedure, motivated by the instanton liquid model, whereas in the second one (Model II) a separable a
Brazilian Journal of Physics. Publicado em: 2007-07
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12. 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