Luis A. Trevisan

Path dependence of the quark nonlocal condensate within the instanton model

Within the instanton liquid model, we study the dependence of the gauge invariant two-point quark correlator on the path used to perform the color parallel transport between two points in the Euclidean space.

Statistical Quark Model for the Nucleon Structure Function

A statistical quark model, with quark energy levels given by a central linear confining potential is used to obtain the light sea‐quark asymmetry, d/ū, and also for the ratio d/u, inside the nucleon. After adjusting a temperature parameter by the Gottfried sum rule violation, and chemical potentials by the valence up and down quark normalizations, the results are compared with experimental data available.A statistical quark model, with quark energy levels given by a central linear confining potential is used to obtain the light sea‐quark asymmetry, d/ū, and also for the ratio d/u, inside the nucleon. After adjusting a temperature parameter by the Gottfried sum rule violation, and chemical potentials by the valence up and down quark normalizations, the results are compared with experimental data available.

Nucleon magnetic moments in light-front models with quark mass asymmetries

We show that the systematic inconsistence found in the simultaneous fit of the neutron and proton magnetics moments in light-front models, disappears when one allows an asymmetry in the constituent quark masses. The difference between the constituent quarks masses is an effective way to include in the nucleon model the effect of the attractive short ranged interaction in the singlet spin channel.

A very simple statistical model to the quarks asymmetries

A simple statistical model is developed with the Fock states being the meson-hadron fluctuations. As expected, a insight about the violation of the Gottfried sum rule is obtained, and also a small difference between the strangeness amount in proton and neutron is explained.

The polarized structure function of the nucleons with a non-extensive statistical quark model

We studied an application of nonextensive thermodynamics to describe the polarized structure function of nucleon, in a model where the usual Fermi-Dirac and Bose-Einstein energy distribution, often used in the statistical models, were replaced by the equivalent functions of the q-statistical. The parameters of the model are given by an effective temperature T, the q parameter (from Tsallis statistics), and the chemical potentials given by the corresponding up (u) and down (d) quark normalization in the nucleon and by Δu and Δd of the polarized functions.

A no extensive statistical model for the nucleon structure function

We studied an application of nonextensive thermodynamics to describe the structure function of nucleon, in a model where the usual Fermi-Dirac and Bose-Einstein energy distribution were replaced by the equivalent functions of the q-statistical. The parameters of the model are given by an effective temperature T, the q parameter (from Tsallis statistics), and two chemical potentials given by the corresponding up (u) and down (d) quark normalization in the nucleon.

Advances on statistical/thermodynamical models for unpolarized structure functions

During the eights and nineties many statistical/thermodynamical models were proposed to describe the nucleons’ structure functions and distribution of the quarks in the hadrons. Most of these models describe the compound quarks and gluons inside the nucleon as a Fermi / Bose gas respectively, confined in a MIT bag[1] with continuous energy levels. Another models considers discrete spectrum. Some interesting features of the nucleons are obtained by these models, like the sea asymmetries d/u and d–u.

On the Kaon-prime anti-s structure function from the strangeness asymmetry in the nucleon

We propose a phenomenological approach based in the meson cloud model to obtain the strange quark structure function inside a kaon, considering the strange quark asymmetry inside the nucleon.

On the kaon' s̄ structure function from the strangeness asymmetry in the nucleon

We propose a phenomenological approach based in the meson cloud model to obtain the strange quark structure function inside a kaon, considering the strange quark asymmetry inside the nucleon.

Nucleon flavor asymmetry in a statistical model of confined quarks

We obtain a simultanously fit to the nucleon experimental data of the flavor asymmetry d/ū in the sea, and the ratio d/u. We use a statistical thermal model, where the quarks are confined inside the nucleon by a linear potential. We adjust the Gottfried sum rule violation with a temperature parameter. To obtain a good fit to the ratio d/ū it was also included the contribution of gluon splitting processes.