Related papers: Baryon structure in a quark-confining non-local NJ…
Recently, it has been shown that the standard Nambu-Jona-Lasinio (NJL) model is not able to reproduce the correct QCD behavior of the gap equation at large density, and therefore a different cutoff procedure at large momenta has ben…
The improved quark mass density- dependent model which includes the coupling between the quarks and a non-linear scalar field is presented. Numerical analysis of solutions of the model is performed over a wide range of parameters. The wave…
Nucleon structure and the origin and nature of the nuclear force are investigated in the context of a QCD-based effective field theory and the path-integral method of hadronization. We start from a microscopic model of quarks and diquarks…
Diquark excitations of dense quark matter are considered in the framework of the Nambu -- Jona-Lasinio model with three types of massless quarks in the presense of a quark number chemical potential $\mu$. We investigate the effective action…
We apply the perturbative chiral quark model (PCQM) to analyse low-energy nucleon properties: electromagnetic form factors, meson-nucleon sigma-terms and pion-nucleon scattering. Baryons are described as bound states of valence quarks…
We argue that precise measurements of charge and magnetic radii can meaningfully constrain diquark models of the nucleon. We construct properly symmetrized, nonrelativistic three-quark wave functions that interpolate between the limits of a…
The Nambu--Jona-Lasinio model (NJL) is extended to incorporate heavy quark spin-symmetry. In this model baryons containing one heavy quark are analyzed as bound-states of light baryons, represented as chiral solitons, and mesons containing…
A simple quark-diquark model for the baryons is constructed as a partial solution to the well known missing resonances problem. A complete classification of the baryonic states in the quark-diquark framework is given and the spectrum is…
The central two-pion exchange NN potential at large distances is studied in the framework of relativistic chiral symmetry and related directly to the nucleon scalar form factor, which describes the mass density of its pion cloud. This…
In this work we explore the effect of pion cloud contributions to the mass of the nucleon and the delta baryon. To this end we solve a coupled system of Dyson-Schwinger equations for the quark propagator, a Bethe-Salpeter equation for the…
The quark-hadron phase transition at finite baryon chemical potential is investigated in the extended Nambu-Jona-Lasinio model in which the scalar-vector eight-point interaction is included holding the chiral symmetry. By comparing a…
We suggest an effective quark model for low-lying baryon octet and decuplet motivated by QCD with a linearly rising confinement potential incorporating the extended Nambu-Jona-Lasinio (ENJL) model with linear realization of chiral U(3)XU(3)…
We apply the quark delocalization and color screening model to nucleon-baryon scattering. A semi-quantitative fit to N-N, N-Lambda and N-Sigma phase shifts and scattering cross sections is obtained without invoking meson exchange. Quarks…
The self-energy of quarks is investigated for various models which are inspired by the Nambu--Jona-Lasinio (NJL) model. Including, beyond the Hartree-Fock approximation, terms up to second-order in the quark interaction, the real and…
This research summarizes work done by myself (Nucl.Phys.{\bf A641} (1998)461), or in collaboration with R. M. Davidson (Phys.Lett.{\bf B348}(1995)163) and H. Weigel and L. Gamberg (Nucl.Phys.{\bf B560}(1999)xx). I will discuss several…
We study the interplay of the chiral and the color superconducting phase transitions in an extended Nambu--Jona-Lasinio model with a multi-quark interaction that produces the nonlinear chiral-diquark coupling. We observe that this nonlinear…
This thesis presents an investigation of meson and baryon properties in the framework of covariant bound-state equations based on the Dyson-Schwinger equations of QCD. Pion and rho-meson, diquark, nucleon and delta-baryon masses are…
Nucleon form factors are calculated on q^2 in [0,3] GeV^2 using an Ansatz for the nucleon's Fadde'ev amplitude motivated by quark-diquark solutions of the relativistic Fadde'ev equation. Only the scalar diquark is retained, and it and the…
We present results of a Monte Carlo simulation of a 2+1 dimensional Nambu - Jona-Lasinio model including diquark source terms. A diquark condensate <qq> is measured as a function of source strength j. In the vacuum phase <qq> vanishes…
The phase structure of the Nambu -- Jona-Lasinio model at zero temperature and in the presence of baryon- and isospin chemical potentials is investigated. It is shown that in the chiral limit and for a wide range of model parameters there…