相关论文: Closing in on the radiative weak chiral couplings

Rare K decays are an important testing ground of the electroweak flavour theory. They can provide new signals of CP-violation phenomena and, perhaps, a window into physics beyond the Standard Model. The interplay of long-distance QCD…

The NA62 experiment at CERN SPS aims to measure the branching ratio of the ultra-rare kaon decay $K^+\to\pi^+\nu\bar{\nu}$ with 10\% precision, collecting $\sim 100$ events, assuming the Standard Model~(SM) branching ratio of $8.4 \times…

NA62, an experiment at the CERN SPS to measure the branching ratio for the decay K+ -> pi+ nu nu-bar with ~10% precision, will observe ~10^13 K+ decays in its fiducial volume, and will thus also be able to carry out a rich program to search…

The CERN NA62 experiment uses a novel "kaon decay-in-flight" technique to observe $K^+ \to \pi^+ \nu \overline{\nu}$. The preliminary result based on the analysis of the full 2016 dataset will be presented. In agreement with the Standard…

The long-term goal of NA62 is to measure the ultra rare K+/- -> pi+/- nu anti-nu decay with a sensitivity of 10^-12 per event. This is done by using the decay - in - flight technique which allows a signal acceptance of ~10% . The aim is to…

The decay rate of $\klpgg$ has been measured with the NA48 detector at the CERN SPS. A total of 2558 $\klpgg$ candidates have been observed with a residual background of 3.2%. The branching ratio is determined to be $(1.36 \pm0.03_{(stat)}…

First preliminary measurement of the direct CP-violating parameter Ag by the NA48/2 experiment at CERN SPS is presented. Using more than 1.6 billions of charged kaon decays into three charged pions, the charge asymmetry in the…

On-shell kaon-nucleon scattering, kaonic atom and kaon condensation are treated on the same footing by means of a chiral perturbation expansion to the next-to-next-to-leading order (``N$^2$LO"). Constraining the low-energy constants in the…

In the last few years it has become possible to study low energy pi pi scattering in kaon decays to three pions, thanks to the high statistics measurement of K+- -> pi+- pi0 pi0 decays performed by the NA48/2 experiment at the CERN SPS. At…

In this paper, radiative decays $\rho^0 \to \pi^+\pi^-\gamma, \pi^0\pi^0\gamma$ ,$\phi \to K^+K^-\gamma, K^0 \bar{K^0}\gamma$ are studied systematically in the U(3)$_L\timesU(3)_R$ chiral theory of mesons. The theoretical differential…

The long-distance and non-local parts of the form factors describing the single-photon mediated $K_{S,L}\to\pi^0\gamma^*\to\pi^0\ell^+\ell^-$ ($\ell = e, \mu$) transitions in the standard model are addressed in QCD in the limit where the…

We derive constraints on combinations of O(p^6) chiral coupling constants by matching a recent two-loop calculation of the pi-K scattering amplitude with a set of sum rules. We examine the validity of the natural expectation that the values…

In this paper we discuss the recent finalized analyses by the KLOE experiment at DA$\Phi$NE: the CPT and Lorentz invariance test with entangled $K^0 \bar{K}^0$ pairs, and the precision measurement of the branching fraction of the decay ${…

We investigate the leading-order amplitudes for weak radiative decays of hyperons in chiral perturbation theory. We consistently include contributions from the next-to-leading order weak-interaction Lagrangian. It is shown that due to these…

The NA48 Collaboration has obtained several new results on kaon and neutral hyperon decays. For hyperons we present new, very precise measurements on the Xi0 lifetime and the decay asymmetries of Xi0 -> Lamda gamma and Xi0 -> Sigma0 gamma.…

A unitary model of the final state kaon pion interaction amplitudes in the B --> K pi pi decays is constructed. The weak decay penguin amplitudes, derived in QCD factorization, are supplemented by phenomenological contributions. The strange…

Rare kaon decays offer a powerful tool for investigating new physics in $s\to d$ transitions. Currently, many of the interesting decay modes are either measured with rather large uncertainties compared to their theoretical predictions or…

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…

In this article we study impact of the lightest vector and scalar resonance multiplets in the pion and kaon decay constants up to next-to-leading order in the $1/N_C$ expansion, i.e., up to the one-loop level. The $F_\pi$ and $F_K$…

A measurement of the form factors of charged kaon semileptonic decays is presented, based on $4.4 \times 10^6$ $K^\pm \to \pi^0 e^\pm \nu_e$ ($K^\pm_{e3}$) and $2.3 \times 10^6$ $K^\pm \to \pi^0 \mu^\pm \nu_{\mu}$ ($K^\pm_{\mu3}$) decays…