Related papers: Improved estimates of rare K decay matrix-elements…

We analyze the CP violating ratio epsilon'/epsilon and rare K and B decays in the MSSM with minimal flavour and CP violation, including NLO QCD corrections and imposing constraints on the supersymmetric parameters coming from epsilon,…

The rare kaon decays K_L -> pi^0 nu {bar nu}, K^+ -> pi^+ nu {bar nu}, K_L -> pi^0 e^+ e^- and K_L -> pi^0 mu^+ mu^- are theoretically very clean and, being strongly CKM suppressed, highly sensitive to New Physics (NP). Recent Flavour…

We present the results of a search for relations between observables that are independent of the Chiral Pertubation Theory (ChPT) Next-to-Next-to-Leading Order (NNLO) Low-Energy Constants (LECs). We have found some relations between…

The amplitudes of $K \rightarrow \pi \gamma^* \rightarrow \pi e^+e^-$ and $K \rightarrow \pi \pi \gamma$ decays have been calculated within chiral Lagrangian approach including higher-order derivative terms and meson loops. The…

We propose analytic approximations of chiral SU(3) amplitudes for the extrapolation of lattice data to the physical meson masses. The method allows the determination of NNLO low-energy constants in a controllable fashion. We test the…

We calculate the long-distance radiative corrections \delta^e_{LD} and \delta^{\mu}_{LD} to the K^0 -> \pi^- e^+ \nu_e and the K^0 -> pi^- \mu^+ \nu_{\mu} decay rates. This analysis includes contributions to the long-distance radiative…

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…

We estimate nonfactorizable 1/$N_c$ contributions in the $K\rightarrow 2\pi$ amplitudes using the approach proposed in our previous work. It is demonstrated that for the conventional (nonpenguin) operators these contributions are close in…

Nucleon weak matrix elements can be extracted from nucleon correlation functions with lattice QCD simulations. The signal-to-noise ratio prohibits the analysis at large source-sink separations and as a consequence, excited state…

$K_{\ell4}$ decays offer several reasons of interest: they allow an accurate measurement of $\pi\pi$-scattering lengths; they provide the best source for the determination of some low-energy constants of ChPT; one form factor is directly…

We compute the leading-log QED, the next-to-leading-log QED-QCD, and the electroweak corrections to the charm quark contribution relevant for the rare decay K+ -> pi+ nu nu-bar. The corresponding parameter P_c(X) is increased by up to 2%…

Using partially twisted boundary conditions we compute the K->pi semi-leptonic form factors in the range of momentum transfers 0 <~ q^2 <= q^2_{max}=(mK-mpi)^2 in lattice QCD with N_f=2+1 dynamical flavours. In this way we are able to…

Starting from the Chiral Perturbation Theory Lagrangian, but keeping different masses for the charged and neutral mesons, and using a previously developed non-perturbative unitary scheme that generates the lightest meson-meson resonances,…

New BABAR measurements are presented for the exclusive rare decays B -> K(*) l+ l- including branching fractions, isospin asymmetries, direct CP violation, and lepton flavor universality for dilepton masses below and above the J/psi…

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 study the properties of the B-->pi and B-->K transition form factors in partially quenched QCD by using the approach of partially quenched chiral perturbation theory combined with the static heavy quark limit. We show that the form…

The matrix elements for $K\rightarrow \pi \pi \l \nu$ decays are described by four form factors $F,G,H$ and $R$. We complete previous calculations by evaluating $R$ at next-to-leading order in the low-energy expansion. We then estimate…

After a short summary of my talk, I discuss $K_{l3}$ decays and elastic $\pi\pi$ scattering in the framework of chiral perturbation theory.

In framework of the chiral perturbation theory we obtain the phenomenological relations between decay branches of rare radiative kaon to pion and leptons $K^+ \to \pi^+ l^+ l^-$ and $K^0_S \to \pi^0 l^+ l^-$ and meson form factors. The…

By employing the perturbative QCD(pQCD) factorization approach, we calculate the branching ratios and CP violating asymmetries of the four $\bar{B}_s^0 \to K\pi$ and $K K $ decays, with the inclusion of all known next-to-leading order (NLO)…