Related papers: phi -> pi0 pi0 gamma Decay within a U(3)x U(3) Lin…
We derive an asymptotic formula a la Luscher for the finite volume correction to the pion decay constant: this is expressed as an integral over the < 3 \pi | A_\mu|0 > amplitude after proper subtraction of the pion pole contribution. We…
We study the $\eta \to \pi^0 \gamma \gamma$ decay via the quark-box diagram in the three-flavor Nambu--Jona-Lasinio model that includes the $U_A (1)$ breaking effect. We find that the $\eta$-meson mass, the $\eta \to \gamma \gamma$ decay…
Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare Pi+ -> Pi0 e+ Nu,(pi_beta) decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed…
The most general amplitude for the radiative pion decay pi -> e nu gamma including terms beyond V-A theory is considered. The experimental constraints on the decay amplitude components are discussed. A model independent presentation of the…
In a sample of 5.3x10^7 phi-decays observed with the KLOE detector at the Frascati phi-factory Dafne we find 605 eta pi0 gamma events with eta --> gamma\gamma and 197 eta pi0 gamma events with eta --> pi+ pi- pi0. The decay phi --> eta pi0…
The $\phi \to K^+K^-,K^{0}_{L},K^{0}_{S},K^{0}\bar K^0$ decays are studied using the method of phenomenological chiral Lagrangians. Calculated values for partial widths for these decay channels are compared with available experimental data.
In this work, we perform a detailed study of the $\tau^-\to\pi^-\pi^0\gamma\nu$ decay process within the resonance chiral theory. We pay special attention to the triple-product asymmetry in the $\tau^-\to\pi^-\pi^0\gamma\nu$ process. The…
We study interference patterns in the phi -> gamma a0 + pi0 rho -> gamma pi eta and phi -> gamma f0 + pi0 rho -> gamma pi0 pi0 reactions. Taking into account the interference, we fit the experimental data and show that the background…
Using the PCAC relation, we derive a compact formula for the pion decay constant $F_{\pi}$ in the nonlocal chiral quark model. For practical calculations this formula may be used both in the Minkowski and in the Euclidean space. For the…
An improved update of the structure and decays of $\rho^0$, $\omega$ and $\phi$ mesons based on a chiral SU(3) Lagrangian, including anomaly terms is presented. We demonstrate that a consistent and quantitatively successful description of…
As first observed by the NA48/2 experiment at the CERN SPS, the $\p0p0$ invariant mass (M00) distribution from $\kcnn$ decay shows a cusp-like anomaly at M00=2m+, where m+ is the charged pion mass. An analysis to extract the pi pi…
A calculation of the pion mass and decay constant at NNNLO in two-flavour chiral perturbation theory is presented. The results are cross-checked by using both the exponential and square root parameterizations of the Goldstone matrix field,…
The decays rho(770) to 4 pi and omega(782) to 5pi are considered in detail in the approach based on the Weinberg Lagrangian obtained upon the nonlinear realization of chiral symmetry, added with the term induced by the anomalous Lagrangian…
We analyze elastic-pion nucleon scattering to third order in the so-called small scale expansion. It is based on an effective Lagrangian including pions, nucleons and deltas as active degrees of freedom and counting external momenta, the…
The claim that the light quark mass ratio (m_d - m_u)/m_s can be extracted from the decay width ratio Gamma(eta' -> pi^0 pi^+ pi^-)/Gamma(eta' -> eta pi^+ pi^-) is critically investigated within a U(3) chiral unitary framework. The…
In this talk, we report our recent work on the pion weak decay constant (F_pi) and pion mass (m_pi) using the nonlocal chiral quark model with the finite quark-number chemical potential (mu) taken into account. Considering the breakdown of…
Using the close relationship between the low--energy constants of chiral perturbation theory and the chiral invariant interactions of the vector meson resonances with the pseudoscalar mesons, we investigate the process $\rho^0 \ra \pi^+…
We examine the radiative decays of the Lambda (1405) to octet baryons, Lambda + gamma and Sigma + gamma. In the limit of SU(3) symmetry the decay rates for these two modes are related, and we compute the leading correction to the relation…
We complement studies of the neutral pion transition form factor pi^0 --> gamma^(*) gamma^(*) with calculations for the electromagnetic decay widths of the processes pi^0 --> e^+ e^-, pi^0 --> e^+ e^- gamma and pi^0 --> e^+ e^- e^+ e^-.…
The temperature dependence of the $\phi$ meson mass and its decay width ($\phi \rightarrow K \bar{K}$)have been studied from an effective non-linear chiral Lagrangian in $SU(3)$. Effective mass has been obtained from the pole position of…