Related papers: A scalar gluonium contribution to $K\rightarrow\pi…
We calculate long distance contributions to $K\to\pi\nu\bar{\nu}\,,\ \pi\pi\nu\bar{\nu}$, and $\pi\pi\pi\nu\bar{\nu}$ modes within the framework of chiral perturbation theory. We find that these contributions to decay rates of $K\to…
We estimate the long distance contribution to the $K^+ \rightarrow \pi^+ \nu \bar\nu$ decay amplitude using chiral perturbation theory. We find that it is likely to be less than a few percent of the part of the short distance contribution…
We present a comprehensive analysis of the contributions to K->pi nu nu decays not described by the leading dimension-six effective Hamiltonian. These include both dimension-eight four-fermion operators generated at the charm scale, and…
It is proposed to compute matrix elements for the (unphysical) $K^0\pi^-\to \pi^-$ transition to determine the next-to-leading order low energy constants of the weak chiral Lagrangian. This allows us to evaluate $K\to(\pi\pi)_{I=0}$ decay…
In this article we analyze the contribution from intermediate spin-0 and spin-2 resonances to the $\tau\to\nu \pi\pi\pi$ decay by means of a chiral invariant Lagrangian incorporating these mesons. In particular, we study the corresponding…
The $K\to\pi\pi$ decay amplitudes are studied within the framework of generalized factorization in which the effective Wilson coefficients are gauge-invariant, renormalization-scale and -scheme independent while factorization is applied to…
We analyze long-distance contributions to the K --> pi pi amplitudes relevant for the Delta I = 1/2 selection rule in the framework of the 1/N_c expansion. We use a modified prescription for the identification of meson momenta in the chiral…
We study the long distance contribution to $K^+\to\pi^+\nu\bar{\nu$ by using chiral perturbation theory. We find that the tree level $O(P^2)$ contribution vanishes identically without assuming the large $N_c$ limit. The leading contribution…
This talk gives a short summary of some work \cite{FGEdeR04} realized in collaboration with E. de Rafael and concerning $K\ra\pi \ell^+ \ell^-$ decays, in a combined framework of Chiral Perturbation Theory and Large--$N\_c$ QCD under the…
The CP conserved non leptonic $K\to \pi \pi \pi$ decays are discussed within the chiral quark model, including chiral perturbation theory corrections. All amplitudes are parameterized in terms of quark and gluon condensate and the…
The long distance contribution to $K^+ \to \pi^+ \nu {\bar \nu} $ is calculated using chiral perturbation theory. The leading contribution comes from $O(p^4)$ tree terms. The branching ratio of the $O(p^4)$ long distance contribution is…
We calculate the $O(p^6)$ corrections to the anomalous form factors appearing in $\pi^+$, $K^+ \to e^+ \nu \gamma,\ \mu^+\nu\gamma$ and $K_{l4}$ decays in Chiral Perturbation Theory. The relevant dimension $6$ terms of the lagrangian are…
We consider the scalar form factor in $\tau \to K\pi \nu_\tau$ decays. It receives contributions both from the scalar resonance $K_0^*(1430)$ and from the scalar projection of off-shell vector resonances. We construct a model for the…
We calculate all of the form factors for the one-photon, $K_L \rightarrow \pi^+ \pi^- \gamma^* \rightarrow \pi^+ \pi^- e^+e^-$ contribution to the $K_L \rightarrow \pi^+ \pi^- e^+e^-$ decay amplitude at leading order in chiral perturbation…
I calculate the leading logarithmic contributions up to two-loop order of the octet part of the K -> pi pi amplitude. This sector of the weak chiral Lagrangian is believed to be the main source of the enhancement of the I=0 relative to the…
The interplay between short- and long-distance contributions to the K_L-->mu+ mu- decay amplitude is analyzed. The long-distance piece is estimated using chiral perturbation theory techniques and large-N_C considerations, leading to a…
I demonstrate that the short distance contribution to K --> Pi Pi decays must be supplemented with large distance effects. A hybrid calculation is outlined based on QCD diagrams supplemented by chiral contributions and Pi-Pi phaseshifts.
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.
We present a calculation of the $K\to\pi\pi$ decay amplitudes from the $K\to\pi$ matrix elements using leading order relations derived in chiral perturbation theory. Numerical simulations are carried out in quenched QCD with the domain-wall…
We calculate long-distance contributions to the amplitudes A(K^0 --> pi pi, I) induced by the gluon and the electroweak penguin operators Q_6 and Q_8, respectively. We use the 1/N_c expansion within the effective chiral lagrangian for…