Related papers: To the problem of 1/Nc approximation in the Nambu-…
Within the Extended Nambu Jona-Lasinio model we analyse the $1/N_c$-corrections to the leading order result $M_S=2M_Q$ where $M_Q$ is the constituent quark mass.
The mass formulas and decay constants of electrically charged and strange pseudoscalar mesons are analyzed within the combined framework of Nambu -- Jona-Lasinio model and the $1/N_c$ expansion up to $\mathcal O(1/N_c^2)$. The light quark…
The Nambu--Jona-Lasinio model is investigated in the $1/N_c$ expansion with the dimensional regularization. At the four-dimensional limit the meson propagators have simple forms in the leading order of the $1/N_c$ expansion. Thus the next…
We show that a remarkable compatibility exists between the results of a potential model with constituent quarks and the 1/Nc expansion mass formula for strange and nonstrange baryon resonances. Such compatibility brings support to the basic…
The influence of mesonic fluctuations on quantities in the Nambu-Jona-Lasinio model is examined in different approximation schemes: an expansion in powers of 1/N_c and an expansion up to one-meson loop in the effective action formalism. It…
We investigate the capabilities of the Nambu--Jona-Lasinio model to describe and reproduce fundamental vacuum properties of Quantum Chromodynamics, notably the hadronic spectrum. Mesons are described as quark-antiquark bound states at the…
Properties of mesons are investigated within the Nambu--Jona-Lasinio model. We include meson-loop corrections, which are generated via a systematic 1/N_c-expansion in next-to-leading order. We show that our scheme is consistent with chiral…
We establish a connection between the quark model results and the $1/N_c$ expansion mass formula used in the description of baryon resonances. We show that a remarkable compatibility exists between the two methods.
We study two aspects of the CFL phase of QCD in the NJL approximation. The first one is the issue of the dependence on \mu of the ultraviolet cutoff in the gap equation, which is solved allowing a running coupling constant. The second one…
We consider a two-flavor Nambu \& Jona-Lasinio model in Hartree approximation involving scalar-isoscalar and pseudoscalar-isovector quark-quark interactions. Average meson fields are defined by minimizing the effective Euklidean action. The…
We continue to study the properties of the light pseudoscalar nonet within the combined framework of Nambu -- Jona-Lasinio model and $1/N_c$ expansion, assuming that current quark masses count of order $\mathcal O(1/N_c)$. The masses,…
We establish a connection between the quark model and the 1/N_c expansion mass formulas used in the description of baryon resonances. We show that a remarkable compatibility exists between the two methods in the light and heavy baryon…
In the present work we use the large-$N_c$ approximation to investigate quark matter described by the SU(2) Nambu--Jona-Lasinio model subject to a strong magnetic field. The Landau levels are filled in such a way that usual kinks appear in…
Within the framework of the $1/N_c$ expansion of four-fermion interaction models, we analyse the next to leading $1/N_c$ corrections to the well known large-$N_c$ result $M_S=2M_Q$ where $M_S$ is the mass of the scalar boson and $M_Q$ is…
By considering the background field method we calculate one-loop polarization corrections to the coupling constant of the flavor-U(5) Nambu-Jona-Lasinio (NJL) model with degenerate up and down quarks. They break flavor and chiral…
Meson loop corrections to baryon axial currents are computed in the 1/N expansion. It is already known that the one-loop corrections are suppressed by a factor 1/N; here it is shown that the two-loop corrections are suppressed by (1/N)^2.…
We propose an extended Nambu--Jona-Lasinio model to include the heavy mesons with the heavy quark symmetry. The quark current-current interaction is generalized to include the heavy quark currents. In order to comply with the heavy quark…
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…
The phase structure of the $d=3$ Nambu-Jona-Lasinio model in curved spacetime is considered to leading order in the $1/N$--expansion and in the linear curvature approximation. The possibility of a curvature-induced first-order phase…
We use the Nambu-Jona-Lasinio model as an effective quark theory to investigate the medium modifications of the nucleon electromagnetic form factors. By using the equation of state of nuclear matter derived in this model, we discuss the…