Related papers: Scalar meson exchange in V->P0P0gamma decays
New ongoing experimental activities that have direct reference to pi^0 decay modes call for a new theoretical study in this area. We will summarize some details and interesting facts that concern main decay modes of this lightest meson.
In the covariant level-classification scheme of hadrons proposed recently, the existence of "chiral particles", scalar and axial-vector mesons as the partners of the ground-state pseudo-scalar and vector mesons, respectively, were predicted…
The N*(1440) -> N pi pi decay is studied by making use of the chiral reduction formula. This formula suggests a scalar-isoscalar pion-baryon contact interaction which is absent in the recent study of Hern{\'a}ndez et al. The contact…
The features of the Resonance Chiral Theory (RChT) related to the description of the lightest scalar resonances, sigma, f0(980) and a0(980), are discussed. Major attention is paid to the fits of the invariant mass distributions in the…
The decay $\eta \to \pi^0 \gamma \gamma$ is discussed in the framework of SU(3) chiral perturbation theory. The process is dominated by the ${\cal{O}}(p^6)$ in the momentum expansion where tree-level amplitudes from the effective Lagrangian…
The arguments are put forward that the many pion decays omega ->2 pi^+ 2 pi^- pi^0 and pi^+ pi^- 3 pi^0 provide an ideal test site for testing the predictions of chiral models of the vector meson decays into many pions. Using the approach…
We reexamine the $\omega \to \pi^{0} \pi^{0} \gamma $ decay, adding the effect of $\omega-\rho$ mixing to the amplitude calculated with the aid of chiral perturbation theory and vector meson dominance. We predict the neutral decay to occur…
After a brief survey of effective field theories, the linear sigma model is discussed as a prototype of an effective field theory of the standard model below the chiral-symmetry-breaking scale. Although it can serve as a toy model for the…
The scalar and vector meson exchange contributions to the doubly radiative decays $\eta^{(\prime)}\to\pi^0\gamma\gamma$ and $\eta^\prime\to\eta\gamma\gamma$ are analysed within the Linear Sigma Model and Vector Meson Dominance frameworks,…
The \pi^0\gamma\gamma vertex is used as an explicit example of the subtleties connected with the application of equation of motion within Chiral Perturbation Theory at the order O(p^6).
We report on a search of relations valid at order $p^6$ in Chiral Perturbation Theory. We have found relations between $\pi\pi$, $\pi K$ scattering, $K_{\ell4}$ decays, masses and decay constants and scalar and vector form factors. In this…
The form factor of the vector meson V conversion transition into the pseudoscalar meson P and the lepton pair l+l- is presented for V=rho0,omega,phi and P=pi0,eta. Our approach is based on the chiral effective field theory with resonances.…
We make a theoretical study of the $\J$ decays into $\omega\pi\pi$, $\phi\pi\pi$, $\omega K \bar{K}$ and $\phi K\bar{K}$ using the techniques of the chiral unitary approach stressing the important role of the scalar resonances dynamically…
We discuss insights that may be drawn from our recent 2 flavour O(a)--improved Wilson quark simulations. We discuss the evidence of the onset of chiral logarithms in the pion decay constant. An overview is given of current extrapolation…
We work out predictions of the Linear Sigma Model for the $\gamma \gamma \to\pi^0 \pi^0$ cross section. We consider the sigma width, which is introduced in a consistent way with chiral Ward identities. The results of Chiral Perturbation…
The $\eta \to \pi^+ \pi^- \pi^0 \gamma$ decay is discussed in the general context of Chiral Perturbation Theory (ChPT), assuming that the low--energy constants (counter--terms) are saturated by vector-meson resonances. The $\eta \to \pi^+…
The high-statistical KLOE data on the $\phi\to\pi^0\pi^0\gamma$ decay are described simultaneously with the data on $\pi\pi$ scattering and the $\pi\pi\to K\bar K$ reaction. The description is carried out taking into account the chiral…
We use heavy vector meson $SU(2)_L \times SU(2)_R$ chiral perturbation theory to predict differential decay distributions for $\tau \rightarrow \rho \pi \nu_\tau$ and $\tau \rightarrow K^* \pi \nu_\tau$ in the kinematic region where $p_V…
We have studied in the framework of Chiral Perturbation Theory (ChPT) the O(p^6) Vector Meson contributions to K -> pi gamma gamma and K(L) -> gamma gamma^*. We construct the most general ChPT lagrangian for the weak…
We analyze the $\gamma\gamma \to \pi^0\pi^0$ and $\gamma\gamma \to \pi^+\pi^-$ reactions using the master formula approach to chiral symmetry breaking. The pertinent vacuum correlators are estimated at tree level, and the results are…