Related papers: Chiral dynamics of many-pion systems
We improve the calculations of the $\eta \to \pi^0 \gamma \gamma$ decay within the context of meson chiral lagrangians. We use a chiral unitary approach for the meson-meson interaction, thus generating the $a_0(980)$ resonance and fixing…
The contribution of the a_1(1260) meson to the amplitudes of the decays rho(770) to 4 pi, omega(782) to 5 pi, and phi(1020) to 5 pi is analyzed in the chiral model of pseudoscalar, vector, and axial vector mesons based on the generalized…
In this talk I summarize a recently proposed mechanism to understand pi pi scattering to 1 GeV. The model is motivated by the 1/Nc expansion to QCD, and includes a current algebra contact term and resonant pole exchanges. Chiral symmetry…
The partial widths of the decays $D^+_s \to \phi \pi^+$ and $D^+_s \to \pi^+ \pi^+ \pi^-$ - nonresonant are computed within the effective quark model with chiral symmetry involving Heavy quark effective theory (HQET) and Chiral perturbation…
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…
The pion decay constant and mass are computed at low temperature within Chiral Perturbation Theory to two loops. The effects of the breaking of Lorentz Symmetry by the thermal equilibrium state are discussed. The validity of the Gell-Mann…
The decays tau -> 3 pi + nu(tau) are analyzed at one loop order in the framework of Generalized Chiral Perturbation Theory, in order to test the sensitivity to the size of spontaneous chiral symmetry breaking parameters, contained in the…
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…
The radiative decays of the phi meson are known to be a good source of information about the a0(980) and f0(980) scalar mesons. We discuss these decays starting from a non-linear model Lagrangian which maintains the (broken) chiral symmetry…
The $\pi$ and $\pi\pi$ decay widths of the excited charm mesons are calculated using a Hamiltonian model within the framework of the covariant Blankenbecler-Sugar equation. The pion-light constituent quark coupling is described by the…
Effective Chiral Lagrangian is derived from QCD in the framework of Field Correlator Method. It contains the effects of both confinement and chiral symmetry breaking due to a special structure of the resulting quark mass operator. It is…
We derive and analyse inequalities relating masses of the lightest pi-pi resonances (rho and sigma) to low energy couplings of the effective chiral Lagrangian in the limit of large number of colours.
Pion photo- and electroproduction has been studied at threshold and in the resonance region below W=2GeV. At threshold pi^0 production can be very well explained within a dynamical model derived from an effective chiral Lagrangian. The…
The hadronic decays eta -> pi pi pi, eta-prime -> pi pi pi and eta-prime -> eta pi pi are investigated within a U(3) chiral unitary approach. Final state interactions are included by deriving the effective s-wave potentials for meson meson…
A consistent description of the pi0 pi0 invariant mass distribution in the phi(1020) -> f0(980) gamma -> pi0 pi0 gamma decay and the pi0 eta in phi(1020) -> a0(980) gamma -> pi0 eta gamma is suggested. A search for the consequences of the…
We construct pi-pi amplitudes that fulfill exact elastic unitarity, account for one loop Chiral Perturbation Theory contributions and include all 1/Nc leading terms, with the only limitation of considering just the lowest-lying nonet of…
We study the low energy pion-hyperon interaction considering effective non-linear chiral invariant Lagrangians including pions, rho mesons, hyperons and corresponding resonances. Then we calculate the S- and P-wave phase-shifts, total cross…
As the pion mass approaches a critical value $m_\pi^\star$ from below, an $S$-wave resonance crosses pion-baryon threshold and becomes a bound state with arbitrarily small binding energy, thus driving the scattering length to diverge. I…
After a brief introduction to chiral perturbation theory, the effective field theory of the standard model at low energies, two recent applications are reviewed: elastic pion-pion scattering to two-loop accuracy and the complete…
We use the chiral quark model to estimate the coefficients of the weak chiral lagrangian as obtained from the bosonization of the ten relevant operators of the $\Delta S = 1$ effective quark lagrangian. All contributions of order $N_c^2$ as…