Related papers: Kaon programme at CERN: recent results
The current status of rare kaon decay experiments is reviewed. New limits in the search for Lepton Flavor Violation are discussed, as are new measurements of the CKM matrix.
Motivated by the prospects for an improved test of lepton universality in K -> l \nu decays by the NA62 experiment at CERN, we study predictions for the possible lepton non-universality in K -> l \nu decays in supersymmetric models.…
Measuring the rate at which the long-lived, neutral kaon decays into a neutral pion, neutrino, and anti-neutrino allows physicists an opportunity to test precise predictions made by the Standard Model. Differences between theoretical…
Recent results are presented for (1) the charge asymmetry in semielectronic kaon decay; (2) the charge radius of the neutral kaon; (3) the decay Klong -> pi0 pi0 e+e-; (4) constraints on rho(CKM) from kaon decays; (5) lepton flavor…
The NA48 experiment at CERN has performed a measurement of direct CP violation in the neutral kaon system, based on data collected in 1997 and 1998. The preliminary result for the parameter $\Re(\epsilon^{\prime}/\epsilon)$ is $(14.0 \pm…
Recent results and future prospects of the particle physics experiments with neutral and charged K-meson (kaon) decays are reviewed. Topics include CP violation, rare decays, leptons in kaon decays, tests of CPT and quantum mechanics,…
The LHCb Collaboration's measurement of R_K = B(B+ -> K+ mu+ mu-)/B(B+ -> K+ e+e-) lies 2.6 sigma below the Standard Model prediction. Several groups suggest this deficit to result from new lepton non-universal interactions of muons. But…
The NA48 experiment, conceived primarily to look for direct CP violation in neutral kaon decays, has recently published the so far most precise determination of the epsilon'/epsilon parameter. After reviewing shortly this result, we report…
The Fermilab KTeV experiment has searched for lepton flavor violating decays of the KL meson in three decay modes. We observe no events in the signal region for any of the modes studied, and we set the following upper limits for their…
The Fermilab HyperCP collaboration is making precision studies of charged hyperon and kaon decays, as well as searches for rare and forbidden hyperon and kaon decays. We report here on measurements of the branching ratios of the…
The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the…
In the Standard Model extended by sterile neutrinos, modified W-l-nu couplings arise, which are able to induce a tree-level enhancement to lepton flavour universality violation in kaon decays. The additional mixing between the active…
The NA48/2 result, based on the data collected during the 2003 run, on direct CP violation in $K^{\pm}\to\pi^{\pm}\pi^0\pi^0$ decay is presented. The main goal of the experiment is to reach a sensitivity at level of $10^{-4}$ in the…
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)}…
We have searched for lepton flavor violating decays of the tau lepton with one or two KS0 mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR)…
We present a precise measurement of the ratio R_K = \Gamma(Ke2(\gamma))/\Gamma(K\mu2(\gamma)) performed with the KLOE detector. The results are based on data collected at the Frascati e^+e^- collider DAFNE for an integrated luminosity of…
$K \rightarrow \pi \ell^+ \ell^-$ decays, $\ell = e, \mu$, will be one of the goals of future kaon facilities, like NA62 (CERN) and K$^0$TO (J-PARC). We review briefly the theoretical status of those processes.
We present the first direct search for lepton flavour violating muon decay mediated by a new light particle X, $\mu^+ \to \mathrm{e}^+\mathrm{X}, \mathrm{X} \to \gamma\gamma$. This search uses a dataset resulting from $7.5\times 10^{14}$…
The first dedicated experiment for the rare kaon decay $K^0_L \to \pi^0 \nu \bar{\nu}$ has been performed by the E391a collaboration at the KEK 12-GeV proton synchrotron. A new upper limit of $2.1 \times 10^{-7}$ at the 90% confidence level…
We report here a measurement of form factors of $K^{\pm}_{\mu 3}$ decay by the NA48/2 experiment at CERN. Using a sample of 3.4$\times10^6$ events we provide preliminary form factor values according to various parametrizations. The slope of…