Related papers: Scalar Mesons within a model for all non-exotic me…
Complex-mass (finite-width) $0^{++}$ nonet and decuplet are investigated by means of exotic commutator method. The hypothesis of vanishing of the exotic commutators leads to the system of master equations (ME). Solvability conditions of…
A new method to find the propagation equation system governing the scattering of an electromagnetic wave by a nonlinear medium is proposed. The aim is to let the effects appear spontaneously, deleting as far as possible the phenomenological…
Enormous progress in physics enriched our knowledge about the particles which build matter. Among them there are mesons, to which this thesis is entirely devoted. The overwhelming majority of mesons is made of `conventional' $q\bar{q}$…
We calculate low-energy meson decay processes and pion-pion scattering lengths in a globally chirally invariant two-flavour linear sigma model exploring the quark content of the scalar mesons f(0)(600) and a(0)(980), as well as f(0)(1370)…
We argue that the low-lying scalar-meson nonet makes part of a subset of a family of infinitely many scalar-meson nonets, which in turn makes part of a family of infinitely many quark-antiquark bound states and resonances. We outline the…
Several theories of beyond-the-standard-model physics predict light scalars that couple to fermions. By extending classical electrodynamics to include an electron-scalar coupling, we calculate the nonlinear Thomson scattering of light…
We study the vector and scalar meson-meson amplitudes up to \sqrt{s}\lesssim 1.4 GeV and their associated spectroscopy. The study has been done considering jointly the N/D method, Chiral Symmetry and implications from large N_c QCD. The N/D…
We study the weight or compositeness of the $\pi\pi$-$K\bar{K}$ and $\pi\eta$-$K\bar{K}$ in the composition of the $f_0(980)$ and $a_0(980)$ resonances, respectively. Either we use the saturation of the total width and compositeness, or we…
The mass spectrum of P-wave mesons is considered in a nonrelativistic constituent quark model. The results show the common mass degeneracy of the isovector and isodoublet states of the scalar and tensor meson nonets, and do not exclude the…
Features of the non-strange \bar n-n and strange \bar s-s scalar mesons are investigated in the Extended Linear Sigma Model (eLSM) with Nf=3 and vector and axial-vector mesons. Our model contains a pure non-strange and a pure strange scalar…
We calculate the threshold $T$ matrices of the light pseudoscalar meson and heavy meson scattering to fourth order in heavy meson chiral perturbation theory. We determine the low-energy constants by fitting to the lattice QCD data points…
It is shown from a very general model and an analysis of data on the lightest 0++ meson nonet that the f0(980) and f0(1200) resonance poles are two manifestations of the same ss state. Similarily the a0(980) and the a0(1450) are likely to…
We study the role of a possible nonet of light scalar mesons in the still interesting $\eta \to 3\pi$ decay process, with the primary motivation of learning more about the scalars themselves. The framework is a conventional non-linear…
Motivated by the $1/N_c$ expansion, we study a simple model in which the pi-K scattering amplitude is the sum of a current-algebra contact term and resonance pole exchanges. This phenomenological model is crossing symmetric and, when a…
We study the influence of mass splitting between the charged and neutral pions and kaons in the Juelich meson exchange model for $\pi\pi$ and $\pi\eta$ scattering. The calculations are performed in the particle basis, which permits the use…
The underlying mixing of quark components of scalar mesons is probed in $\pi K$ scattering within a generalized linear sigma model that contains two scalar meson nonets and two pseudoscalar meson nonets (a quark-antiquark and a four-quark).…
Lattice gauge calculations predict the existence of glueballs. In particular a scalar glueball is firmly expected at a mass of about 1730 MeV. This prediction has led to an intense study of scalar isoscalar interactions and to the discovery…
We present a simple model of the interface between a local homogeneous medium and a potentially nonlocal metamaterial/photonic crystal. This model allows us to calculate the scattering matrix elements of the interface for a plane wave of…
We show on gauge invariance grounds that the fine threshold phenomenon is discovered in the radiative decays phi->gamma a0->gamma pi0 eta and phi->gamma f0->gamma pi0pi0. This enables to conclude that production of the lightest scalar…
The spectroscopy of light, strange baryons have been an important aspect with still unknown resonances and intrinsic baryonic properties. The present document is focused on the $\Delta$ baryons unlike earlier work, here all the four isospin…