Related papers: On the scalar nonet in the extended Nambu Jona-Las…
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.
We review the spectrum of lightest scalar resonances recently determined using dispersion techniques. The conceptual difference between the pole mass and the bare mass (or the line--shape mass) is stressed. The nature of the lightest…
In the framework of the local Nambu-Jona-Lasinio model the radiative decay widths of the scalar mesons $f_0(980)$ and $a_0(980)$ into $\rho\gamma$ and $\omega \gamma$ are calculated. The contributions of the quark loops and the meson loops…
The two-photon decay widths of scalar mesons \sigma(600), f_0(980) and a_0(980) are calculated in framework of the local Nambu-Jona-Lasinio model. The contributions of the quark loops (Hartree-Fock approximation) and the meson loops (next…
In the chiral unitary approach, we have studied the single Cabibbo-suppressed decays $\Lambda_c\to pK^+K^-$ and $\Lambda_c \to p \pi^+\pi^-$ by taking into account the $s$-wave meson-meson interaction as well as the contributions from 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,…
The interactions between the f_0(980) and a_0(980) scalar resonances and the lightest pseudoscalar mesons are studied. We first obtain the interacting kernels, without including any ad hoc free parameter, because the lightest scalar…
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 quark antiquark components of the U(3) lightest scalar meson nonet are investigated by considering the Nambu-Jona-Lasinio model with flavor-dependent coupling constants that were derived by considering (non-perturbative) gluon…
It is shown that one can fit the available data on the a0(980), f0(980), f0(1300) and K*0(1430) mesons as a distorted 0++ qq bar nonet using very few (5-6) parameters and an improved version of the unitarized quark model. This includes all…
The $D^0$ decay into $K^0_s$ and a scalar resonance, $f_0(500)$, $f_0(980)$, $a_0(980)$, is studied obtaining the scalar resonances from final state interaction of a pair of mesons produced in a first step in the $D^0$ decay into $K^0_s$…
I present the results of a recent calculation to determine the number of strange scalar resonances below 1.8 GeV based on the analytic properties of the experimental pi K scattering amplitude. Only one resonance was found in the data, and…
The two-photon decay widths of scalar mesons \sigma(600), f_0(980) and a_0(980) as well a_0 -> \rho(\omega)\gamma and f_0 -> \rho(\omega)\gamma are calculated in the framework of the local Nambu-Jona-Lasinio model. The contributions of the…
First radial excitations of the isoscalar and isovector scalar mesons f_0(400-1200), f_0(980) and a_0(980) are investigated in the framework of a nonlocal version of a chiral quark model of the Nambu--Jona-Lasinio type. It is shown that…
Two photon decays of scalar mesons f_0(980), a_0(980), \sigma(600) in the quark Nambu - Jona - Lasinio (NJL) model are calculated. The contributions of the meson loops are taken into account along with the quark loops (Hartree - Fock…
We consider the contribution of scalar resonances to hadronic light-by-light scattering in the anomalous magnetic moment of the muon. While the $f_0(500)$ has already been addressed in previous work using dispersion relations, heavier…
Nambu-Jona-Lasinio model used to investigate low energy phenomena is nonrenormalizable, therefore the results depend on the regularization parameter in general. A possibility of the finite in four-dimensional limit and even the…
By scaling the parameters of meson-meson unitarized Chiral Perturbation Theory amplitudes according to the QCD large N_c rules, one can study the spectroscopic nature of light meson resonances. The scalars sigma, kappa f_0(980) and,…
A short review on light scalar mesons is performed both in experiment and theory. A naive model, constrained by D branching ratios, is derived in order to make predictions on the wave functions of the $f_0(600)$ and $a_0(980)$ mesons. This…
We report our results on the nature of the lightest scalar resonances, where we show that a quark-antiquark or glueball interpretation of the scalars f_0(600) and K^*_0(800) requires a very unnatural fine tuning to satisfy 1/N_c-expansion…