Nonlocal chiral quark models with wavefunction renormalization: Sigma properties andπ−πscattering parameters

Abstract

We analyze the sigma meson mass and width together with the pion-pion scattering parameters in the context of nonlocal chiral quark models with wave function renormalization (WFR). We consider both nonlocal interactions based on the frequently used exponential form factor, and on fits to the quark mass and renormalization functions obtained in lattice calculations. In the case of the sigma properties, we obtain results which are less dependent on the parametrization than in the standard local Nambu-JonaLasinio model, and which are in reasonable agreement with the recently reported empirical values. We also show that the inclusion of the WFR tend to improve the description of the -scattering parameters, with the lattice inspired parametrization providing the best overall results. Finally, we analyze the connection of the nonlocal quark models discussed here with chiral perturbation theory, and present the model predictions for the low-energy constants relevant for -scattering to Oð4Þ in the chiral expansion.

Strong magnetic fields in a nonlocal Polyakov chiral quark model

“…The "nonlocal Polyakov-NambuJona-Lasinio" (nlPNJL) models considered here are a sort of nonlocal extensions of the PNJL model that intend to provide a more realistic effective approach to QCD. In fact, nonlocality arises naturally in the context of successful descriptions of low-energy quark dynamics [11,12], and it has been shown [13] that nonlocal models can lead to a momentum dependence in quark propagators that is consistent with LQCD results. It is also found that in this framework one obtains an adequate description of the properties of light mesons at both zero and finite temperature/density (see e.g.…”

Deconfinement and chiral restoration in nonlocal SU(3) chiral quark models

“…[18], for the SU(2) version of the model these functional forms can very well reproduce the momentum dependence of mass and wave function renormalization obtained in lattice calculations.…”

“…[18] and [26], within two-and three-flavor parameterizations respectively. As discussed in those articles, this can be in part attributed to the fact that our fit to lattice data for the function Z(p) is based on the calculations in Ref.…”

Pion radiative weak decays in nonlocal chiral quark models

“…The explicit expressions of G M (p 2 ), as well as those of the gap equations mentioned above, can be found in Ref. [26]. …”

“…the case of the instanton liquid model [13] and the Schwinger-Dyson resummation techniques [14], and also lattice QCD calculations [15][16][17] indicate that quark interactions should act over a certain range in momentum space. Indeed, nonlocal chiral quark models have been successfully applied to study different hadron observables [18][19][20][21][22][23][24][25][26].…”