相关论文: Symmetries and Ambiguities in the linear sigma mod…

The $U_L(3)\times U_R(3)$ Linear Sigma Model (LSM) with quark degrees of freedom is used to show that radiative corrections generate undetermined finite contributions. Their origin is related to surface terms which are differences between…

We study the dynamical consequences imposed on effective chiral field theories such as the quark-level SU(2) linear $\sigma$ model (L$\sigma$M) due to the fundamental constraints of massless Goldstone pions, the normalization of the pion…

This review of the quark-level linear \sigma model is based upon the dynamical realization of the pseudoscalar and scalar mesons as a linear representation of SU(2) x SU(2) chiral symmetry, with the symmetry weakly broken by current quark…

First we summarize the quark-level linear $\sigma$ model compositeness conditions and verify that indeed $m_\sigma = 2 m_q$ when $m_\pi = 0$ and $N_c=3$, rather than in the $N_c\to\infty$ limit, as is sometimes suggested. Later we show that…

Dynamical chiral symmetry breaking is described within the linear sigma model of QCD coupled to quarks. The main technical tool used for this intrinsically non--perturbative problem is an exact renormalization group equation for the quantum…

We explore the link between the chiral symmetry of QCD and the numerical results of the light-front quark model, analyzing both the two-point and three-point functions of the pion. Including the axial-vector coupling as well as the…

The implications of chiral $SU(3)_L \times SU(3)_R$ symmetry and heavy quark symmetry for the radiative decays $D^{*0}\to D^0\gamma$, $D^{*+}\to D^+\gamma$, and $D_s^*\to D_s\gamma$ are discussed. Particular attention is paid to $SU(3)$…

We describe an extension of the hadronic SU(3) non-linear sigma model to include quarks. As a result, we obtain an effective model which interpolates between hadronic and quark degrees of freedom. The new parameters and the potential for…

To analyze an electromagnetic and strong hadron processes at low energies, we consider the renormalizable model with the U0(1) x U(1) x SU(2) gauge symmetry. This approach is based on the linear sigma-model extended by the gauge and…

We investigate the restoration of chiral symmetry at finite temperature in the SU(2) quark meson model where the mean field approximation is compared to the renormalized version for quarks and mesons. In a combined approach at finite…

We revisit the renormalization prescription for the quark-meson model in an extended mean-field approximation, where vacuum quark fluctuations are included. At a given cutoff scale the model parameters are fixed by fitting vacuum…

Within renormalizable theories the triangle diagram correctly reproduces the lifetime of the neutral pion $\pi ^0$. However, effective relativistic quark models which contain a second scale besides the quark mass seem unable to give the…

We review some recent progress in the theory of electroweak radiative corrections in semileptonic decay processes. The resurrection of the so-called Sirlin's representation based on current algebra relations permits a clear separation…

Using chiral symmetry we investigate the leading SU(3) violation in light-cone distribution functions phi_M(x) of the pion, kaon, and eta. It is shown that terms non-analytic in the quark masses do not affect the shape, and only appear in…

The quark-level linear sigma model is employed to compute a variety of electromagnetic and weak observables of light mesons, including pion and kaon form factors and charge radii, charged-pion polarizabilities, semileptonic weak $K_{\ell3}$…

Using the linear sigma model, we study the evolutions of the quark condensate and of the nucleon mass in the nuclear medium. Our formulation of the model allows the inclusion of both pion and scalar-isoscalar degrees of freedom. It…

The introduction of axions gives rise to additional one-loop diagrams for the two-photon decays of neutral pions via axion-pion mixing. We compute this correction that has been overlooked in existing calculations, within the framework of…

Chiral loop corrections for hadronic properties are considered in a constituent quark model. It is emphasized that the correct implementation of such corrections requires a sum over intermediate hadronic states. The leading non-analytic…

We investigate the thermal properties of hadrons in two-color quantum chromodynamics (QC$_2$D) using the functional renormalization group (FRG) method, with particular focus on modifications of the $U(1)$ axial anomaly effects. The hadrons…

We study the approximation of chiral quark models with simpler models, obtained via gradient expansion. The resulting Lagrangian of the type of the linear sigma-model contains, at the lowest level, an additional term with two derivatives.…