Related papers: Which scalar meson is the glue-state ?
Light scalar hadrons are often understood as dynamically generated resonances. These arise as `companion poles' in the propagators of $q\bar{q}$ seed states when accounting for meson-loop contributions to the self-energies of the latter.…
We consider the two-flavor version of the extended linear sigma model (eLSM), which contains (pseudo)scalar and (axial-)vector quark-antiquark mesons, a scalar glueball (predominantly corresponding to $f_{0}(1710)$), as well as the nucleon…
The holographic Witten-Sakai-Sugimoto model is an almost parameter-free approximation to large-N QCD with chiral quarks that in a number of cases gives surprisingly good quantitative results for light meson physics. It also allows for…
We use Ward identities of broken scale invariance to infer the amount of scalar glueball--$\bar{q}q$ meson mixing from the ratio of quark and gluon condensates in the QCD vacuum. Assuming dominance by a single scalar state, as suggested by…
Using ideas underlying the flavour-blind "Nijmegen Unitarised Meson Model" we try to understand on the basis of a system of Schroedinger equations with one meson-meson and one (spinless) quark-antiquark channel coupled by a simple…
Recent numerical calculations of the glueball spectrum in QCD, in SU($N$) Yang-Mills theory in the large-$N$ limit and in candidate theories of strongly interacting dynamics beyond the standard model (in which the lowest-lying scalar plays…
We analyse the meson spectrum in quenched QCD using lattice gauge theory. By studying hadron propagation with a variety of operators (both smeared and local), we are able to extract the ground state and first excited state masses with…
An effective chiral lagrangian of order $p^2$, describing the interaction of light pseudoscalar (PS) mesons with $\eta'$-meson and PS-glueball, has been determined taking into consideration the renorm-group requirements imposed by QCD…
The existence of non-q\bar{q} hadrons such as glueballs and hybrids is one of the most important qualitative questions in QCD. The COMPASS experiment offers the possibility to unambiguously identify such states and map out the glueball and…
The main aim of our study is to understand the nature of some conventional and non-conventional mesonic states by applying effective QFT models. We start from the relativistic Lagrangians containing a unique $q\bar{q}$ seed state which is…
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…
In a U(3)x U(3) quark chiral model of the Nambu-Jona-Lasinio type with the 't Hooft interaction, the ground scalar isoscalar mesons and a scalar glueball are described. The glueball (dilaton) is introduced into the effective meson…
The effect of quark-gluon vertex dressing on the ground state masses of the u/d-quark pseudoscalar, vector and axialvector mesons is considered with the Dyson-Schwinger equations. This extends the ladder-rainbow Bethe-Salpeter kernel to…
We study light scalar mesons in the AdS/QCD soft-wall model with a background dilaton field, to investigate the features of this approach in describing QCD properties in the strong coupling regime. We find that the masses and decay…
For a two-particle bound-state equation closer to its Bethe-Salpeter origins than Salpeter's equation, with effective-interaction kernel deliberately forged such as to ensure, in the limit of zero mass of the bound-state constituents, the…
We estimate the decay constants $f_\pi$ and $f_K$ of the light mesons within a relativistic quantum-field model of interacting quarks and gluons confined analytically. The necessary physical parameters, the quark masses $m_u$ and $m_s$, the…
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…
We study light scalar mesons in the AdS/QCD soft-wall model with a background dilaton field. The masses and decay constants are compatible with experiment and QCD determinations if $a_0(980)$ and $f_0(980)$ are identified as the lightest…
A collective treatment of the I=0 scalar mesons below 2 GeV [sigma (550), f0(980), f0(1370), f0(1500) and f0(1710)] in a non-linear chiral Lagrangian framework that is constrained by the mass and the partial decay widths of the I=1/2,1…
Inspired in the AdS/CFT correspondence, a variety of holographic phenomenological models have been proposed in the last years to describe non-perturbative aspects of strong interactions. These models are denominated as AdS/QCD. In this work…