Related papers: Light scalar mesons and two-kaon correlation funct…
We perform the analysis of the preliminary data on $e^+e^-\to\phi\to\gamma f_0(980)\to\gamma\pi^0\pi^0$ reaction simultaneously with the data on $\pi\pi$ scattering and reactions $J/\psi\to\phi\pi^+\pi^-$ and…
Following the re-establishment of the \sigma(600) and the \kappa(900), the light scalar mesons a_0(980) and f_0(980) together with the \sigma(600) and the \kappa(900) are considered as the chiral scalar partner of pseudoscalar nonet in…
The wave function of a light pseudoscalar meson is considered and nonperturbative corrections as signaled by perturbation theory are calculated. Two schemes are used, the massive gluon and the running coupling scheme. Both indicate the…
Strong interactions between pairs of the K+ K- and K0 K0bar mesons can be studied in radiative decays of phi(1020) mesons. We present a theoretical model of the reactions e+ e- --> phi --> K+ K- gamma and e+ e- --> phi --> K0 K0bar gamma.…
The $\gamma p \to K^+ \pi^0 \Lambda$ and $\gamma p \to K^+ \pi \Sigma $ reactions are studied in the kinematic region where the $\pi^0 \Lambda$(1116) and $\pi\Sigma$(1192) pairs originate dominantly from the decay of the $\Sigma$(1385) and…
The structure of the light scalar mesons is elucidated by the investigation of the S-matrix poles and the q-qbar spectral density in a coupled channel model that includes pi-pi, K-Kbar and q-qbar channels. It is shown that the dynamical…
The light-quark non-strange scalar mesons a0(980), f0(980), f0(1370), a0(1450), f0(1500) and f0(1710) are of great interest as there is no generally accepted view of their structure which can encompass q-q-qbar-qbar, molecular, q-qbar and…
The COMPASS collaboration, as a part of their hadron spectroscopy program, is going to measure the radiative decay widths of light-quark mesons via the Primakoff reactions. In this letter we study the photon couplings of light-quark q qbar…
In the light scalar meson sector (M < 1.8 GeV) one expects at least one q qbar nonet and a glueball, possibly also multi-quark states. We discuss the present phenomenological evidence for sigma and kappa particles; if real, they could be…
CERN COMPASS plans measurements of gamma-pi and gamma-K interactions using 50-280 GeV pion (kaon) beams and a virtual photon target. Pion (kaon) polarizabilities and radiative transitions will be measured via Primakoff effect reactions such…
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…
It is presented a critical consideration of all unusual properties of the scalar $a_0(980)$ and $f_0(980)$-mesons in the four-quark, two-quark and molecular models. The arguments are adduced that the four-quark model is more preferable. It…
New high statistics Belle data on the $\gamma\gamma\to\pi^+\pi^-$ reaction cross section measured in the range of pion-pair invariant masses $\sqrt{s}$ between 0.8 GeV and 1.5 GeV are analyzed to clarify the current situation around the…
The surprising thing is that the light scalar meson problem, arising 50 years ago from the linear sigma model (LSM) with spontaneously broken chiral symmetry, has become central in the nonperturbative quantum chromodynamics (QCD), because…
A theoretical model of the reactions e+ e- --> K+ K- gamma and e+ e- --> K0 K0bar gamma has been derived. The strong interaction between kaons is taken into account using a general form of the K Kbar scattering amplitude. It is shown that…
The spectroscopic parameters and partial decay widths of the light mesons $ a_0(980) $ and $K_{0}^{\ast}(800)$ are calculated by treating them as scalar diquark-antidiquark states. The masses and couplings of the mesons are found in the…
Masses and widths of the four light scalar mesons $\sigma$, $\kappa$, $a_0$(980) and $f_0$(980) may be reproduced in a model where mesons scatter via a $q\bar{q}$ loop. A transition potential is used to couple mesons to $q\bar{q}$ at a…
A coupled channel model is used to study the nature of the scalar mesons produced in the decay phi - gamma pi pi. The KKbar molecular picture of f0(980) is found to be in a good agreement with the recent experimental data from SND and…
A separable potential model of three coupled channels (pion-pion, kaon-antikaon and an effective four pion) has been constructed and applied in the analysis of the isoscalar S-wave pion-pion and kaon-antikaon phase shifts and inelasticities…
We study the reactions $\gamma\gamma\rightarrow \pi^0\pi^0$, $\pi^+\pi^-$, $K^0\bar{K}^0$, $K^+K^-$, $\eta \eta$ and $\pi^0\eta$ based on a chiral Lagrangian with dynamical light vector mesons as formulated within the hadrogenesis…