Related papers: Aspects of radiative K^+_e3 decays
The branching ratios of the measured decay $K_L\to\pi^+\pi^-e^+e^-$ and of the still unmeasured decay $K^+\to\pi^+\pi^0e^+e^-$ are calculated to next-to-leading order in Chiral Perturbation Theory (CHPT). Recent experimental results are…
Using the full data set of the NA48/2 experiment, the decay K+- -> pi+- e+ e- gamma is observed for the first time, selecting 120 candidates with 7.3 +- 1.7 estimated background events. With K+- -> pi+- pi0D as normalisation channel, the…
Decays $K^{+} \rightarrow \mu^{+}\nu_{\mu} \nu \bar \nu$ and $K^{+}\rightarrow e^{+}\nu_{e} \nu \bar \nu$ are examined to the leading order in momenta in the framework of Chiral Perturbation Theory. Predictions of the Standard Model for the…
We evaluate the rare radiative kaon decays K_{L,S} -> 3 gamma. Applying the requirements of gauge invariance and Bose symmetry, we derive a general form of the decay amplitude, including both parity-conserving and parity-violating…
A short overview of theoretical predictions for various kaon decays is presented. Particular attention is devoted to pure and radiative nonleptonic decays in the framework of Chiral Perturbation Theory. The relevance of KLOE's future…
The decays $K \to \pi l^{+} l^{-}$, $K \to \pi \gamma \gamma $ and $K \to \pi \nu {\bar \nu}$ are investigated using the higher order terms of the chiral perturbation theory. The counterterms induced by strong, weak and electromagnetic…
In this talk, we present our recent work on the $K\ra\pi \bar{l} l$ decays in a combined framework of chiral perturbation theory and Large--$N_c$ QCD under the dominance of a minimal narrow resonance structure. The proposed description…
We review some new developments in the theoretical description of the processes K ->pi gamma gamma, K_L ->gamma l^+ l^-, K_L ->pi^0 e^+ e^- and K_L ->mu^+ mu^-.
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…
We evaluate the branching ratios for the decays $K\rightarrow \pi\pi\pi e\nu$ at leading order in chiral perturbation theory and give an isospin relation for the decay rates.
We review some recent theoretical results on radiative rare kaon decays. Particular attention is devoted to the channels $K\to \pi l\bar{% l}$ and $K\to \pi \pi \gamma$, where we are (or might be) able to extract the short distance…
The charged kaon decay channel K_l3gamma^+ allows for studies of direct CP violation, possibly due to non-standard mechanisms, with the help of T-odd correlation variables. In order to be able to extract a CP-violating signal from…
With usage of the Low theorem the general expression for amplitude of radiative kaon decay \k+ \to \pi+\pi0\gamma is determined.
We compute the branching ratio for $\Delta\rightarrow Ne^+e^-$ and $\Delta\rightarrow N\mu^+\mu^-$ in chiral perturbation theory and find that both decays should be observable at CEBAF. With sufficiently low thresholds on the $e^+e^-$…
We discuss radiative transitions of a charged kaon to a pion and two photons. In particular, we have a closer look at radiative corrections for the $K^+\to\pi^+\ell^+\ell^-$ decays and present the branching ratio of the…
We discuss radiative corrections to K_{e3} and pi_{e3} decays within chiral perturbation theory with virtual photons and leptons. We then present the extraction of the CKM elements V_{us} and V_{ud} using the presently available…
Recent results from the first phase of the E787 experiment and an update on the current status are presented. From the first phase the limit on the K+ -> pi+ nu nu (pnn) branching ratio is BR(pnn) < 2.4e-9 (90%CL). An observation of the…
We investigate the rare radiative eta decay modes $\eta\to\pi^+\pi^-\gamma\gamma$ and $\eta\to\pi^0\pi^0\gamma\gamma$ within the framework of chiral perturbation theory at $O(p^4)$. We present photon spectra and partial decay rates for both…
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…
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…