Mesons
Mostrando 25-36 de 71 artigos, teses e dissertações.
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25. Open charm tomography of cold and hot nuclear matter
We identify the nuclear effects that modify the cross sections for open heavy flavor production in proton-nucleus and nucleus-nucleus collisions. In p+A reactions, we calculate and resum the coherent nuclear-enhanced power corrections from the final-state parton scattering in the medium. We find that single and double inclusive open charm production can be s
Braz. J. Phys.. Publicado em: 2007-06
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26. Distribution amplitudes of light mesons and the photon in the instanton model
The leading- and higher-twist distribution amplitudes of the pion, the rho-meson and real and virtual photons are analyzed in the instanton liquid model.
Braz. J. Phys.. Publicado em: 2007-06
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27. Melting rho meson and thermal dileptons
We first give a brief survey of theoretical evaluations of light vector mesons in hadronic matter, focusing on results from hadronic many-body theory. We emphasize the importance of imposing model constraints in obtaining reliable results for the in-medium spectral densities. The latter are subsequently applied to the calculation of dilepton spectra in high-
Braz. J. Phys.. Publicado em: 2007-06
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28. Charmed scalar mesons masses within the QCD sum rules framework
In this work, we evaluate the D+sJ(2317), D(0)0(2308), D(0)0(2407) and D+0(2403) masses. These are scalar mesons recently discovered in the BABAR, BELLE and FOCUS Collaborations. The nature of these particles is intensely discussed nowadays. We treat them as a diquark-antidiquark configuration and treat the problem using the QCD sum rules (QCDSR) approach.
Brazilian Journal of Physics. Publicado em: 2007-03
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29. Charmed-meson scattering on nucleons in a QCD Coulomb gauge quark model
The scattering of charmed mesons on nucleons is investigated within a chiral quark model inspired on the QCD Hamiltonian in Coulomb gauge. The microscopic model incorporates a longitudinal Coulomb confining interaction derived from a self-consistent quasi-particle approximation to the QCD vacuum, and a traverse hyperfine interaction motivated from lattice si
Brazilian Journal of Physics. Publicado em: 2007-03
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30. Investigating the tetraquark structure of the new mesons
Using the QCD sum rule approach we investigate the vertex associated with the decay D0(0+)-> D+pi-, where the scalar meson D0(0+) is considered as a four-quark state $(cd)(\bar{u}\bar{d})$. Although our results for the mass and partial decay width are smaller than the mass and the total decay width of the broad scalar meson D0*0(2308) reported by BELLE Colla
Brazilian Journal of Physics. Publicado em: 2007-03
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31. Small-x physics at coherent pA/AA interactions at LHC
We report on our recent investigations in photonuclear production of heavy quarks and vector mesons in ultraperipheral collisions at nucleus-nucleus and proton-nucleus reactions. They are initiated by quasi-real photons coming from one of the nuclei or hadron in interactions taking place at large impact parameter. We focus on the role played by the high ener
Brazilian Journal of Physics. Publicado em: 2007-03
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32. QCD Green functions and their application to hadron physics
In a functional approach to QCD the infrared behaviour of Landau gauge Green functions is investigated. It can be proven that the ghost Dyson-Schwinger equation implies the Gribov-Zwanziger horizon condition. Its relation to the Kugo-Ojima confinement scenario is elucidated. Positivity violation for gluons is demonstrated, and the analytic structure of the g
Brazilian Journal of Physics. Publicado em: 2007-03
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33. Fenomenologia em cromodinâmica quântica com propagador de glúon modificado
A aplicabilidade e usos de propagadores de glúon modificados na Cromodinâmica Quântica (QCD) em diferentes espécies de processos é analisada. Os propagadores modificados de glúon são obtidos por diversos métodos, em especial, as equações de Dyson-Schwinger e simulações numéricas em teoria de campos na rede. Os processos em que estes propagadores
Publicado em: 2007
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34. Um novo modelo para decaimentos de mésons
A representação de Fock-Tani é um formalismo de teoria de campos para tratar problemas envolvendo simultaneamente partículas compostas e seus constituintes. O formalismo foi originalmente desenvolvido para tratar problemas de física atômica e mais tarde estendido para problemas da física hadrônica. Nesta dissertação, inicialmente apresentamos uma b
Publicado em: 2007
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35. Físicos, mésons e política: a dinâmica da ciência na sociedade
Revista Brasileira de Ensino de Física. Publicado em: 2007
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36. 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