Related papers: Scalar Mesons: A Chiral Lagrangian Framework for t…

Using conventional constituent-quark model, $I=1/2$ scalar $\kappa$, vector $K^\ast(892)$, and axial vector $K_1$ mesons are studied in the asqtad-improved staggered fermion with the wall-source and point-sink interpolators. The mass ratio…

We base our chiral symmetry approach on the quark-level linear sigma model Lagrangian. Then we review the Nambu--Goldstone theorem with vanishing pi, K, eta_8 masses. Next we dynamically generate the pi, K, eta_8 masses away from the chiral…

Scalar mesons are a key expression of the strong physics regime of QCD and the role condensates, particularly $<q{\bar q}>$, play in breaking chiral symmetry. What new insights have been provided by recent experiments on $D, D_s$ and…

We compute from lattice QCD in the valence (quenched) approximation the partial decay widths of the lightest scalar glueball to pairs of pseudoscalar quark-antiquark states. These predictions and values obtained earlier for the scalar…

The center-of-gravity rule is tested for heavy and light-quark mesons. In the heavy-meson sector, the rule is excellently satisfied. In the light-quark sector, the rule suggests that the $a_0(980)$ could be the spin-partner of $a_2(1320)$,…

We propose a new nonet scheme for scalar mesons consisting of $f_{0}(980)$, $a_{0}(980)$, $K_{0}^{\ast}(1430)$, and $f_{0}(1770)$, regarding them as quark-antiquark $P$-wave states classified by $\mathrm{SU}(3)$ light flavor symmetry. We…

We introduce coupled channels of Bethe-Salpeter mesons both in the boundstate equation for mesons and in the mass gap equation for chiral symmetry. Consistency is insured by the Ward Identities for axial currents, which preserve the…

We present a chiral effective model which exhibits all the known symmetry features of the QCD Lagrangian. The extended Linear Sigma Model (eLSM) includes (pseudo-)scalar and (axial-) vector mesons, glueballs, and baryons. It has proven to…

In this article, we take the point of view that the $0^{++}$ nonet mesons below $1 GeV$ are diquark-antidiquark states $(qq)_{\bar{3}}(\bar{q}\bar{q})_3$, and devote to determine their masses in the framework of the QCD sum rules approach…

We consider the matrix elements of the left-handed flavor-conserving four-quark operators in the nucleon and pion states. Using chiral symmetry, we derive relationships among these matrix elements. We argue that the $\Delta I = 1/2$ rule of…

Preliminary results of a work in collaboration with M.R. Pennington are presented. Extending a scheme introduced by Tornqvist, we investigate a dynamical model in which the spectrum of scalar mesons can be derived, with the aim of locating…

The corrections to the current algebra mass formulae for the pseudoscalar mesons are analyzed by means of a simultaneous exansion in powers of the light quark masses and powers of 1/N. A set of mass formulae is derived, including an…

We investigate the scalar meson mass dependence on the chiral phase transition in the framework of an SU(3), (axial)vector meson extended linear sigma model with additional constituent quarks and Polyakov loops. We determine the parameters…

The chiral symmetry relation and scaling of the overlap fermions are studied numerically on the quenched lattices at 3 couplings with about the same physical volume. We find that the generalized Gell-Mann-Oakes-Renner relation is satisfied…

We study the possibility that the light scalar mesons are (qbar qbar q q) states rather than (qbar q). We perform a lattice QCD calculation of pseudoscalar meson scattering amplitudes, ignoring quark loops and quark annihilation, and find…

Basing on the previously performed K-matrix analysis of experimental data, we investigate, in the framework of the propagator matrix (D-matrix) technique, the 1100-1900 MeV mass region, where overlapping resonances $f_0(1300)$, $f_0(1500)$,…

In terms of the heavy chiral Lagrangian and the unitarized coupled-channel scattering amplitude, interaction between the heavy meson and the light pseudoscalar meson is studied. By looking for the pole of scattering matrix on an appropriate…

Interactions of $a_2, K^*_2, f_2$ and $f_2'$ tensor-mesons with low-energy $\pi, K, \eta, \eta'$ pseudo-scalar mesons are constrained by chiral symmetry. We derive a chiral Lagrangian of tensor mesons in which the tensor mesons are treated…

We extend the chiral quark model for $u$, $d$, $c$ and $b$ quarks with vector mesons, which we proposed in the previous analysis, to a model with the $s$ quark. We include the nonet pseudo-scalar and vector mesons together with the singlet…

The mass spectra and wave functions of both $1S$ and $2S$ state heavy pseudoscalar ($P$) and vector ($V$) mesons are analyzed within the light-front quark model. Important empirical constraints employed in our analysis of the mass spectra…