Related papers: CPV tests with rare kaon decays
We report the recent results on rare kaon decays from the NA48/2 experiment. The precise measurement of direct photon emission (DE) in the decay K+- -> pi+- pi0 gamma and its interference (INT), with the INT amplitude being observed for the…
Recent results by the NA48 collaboration on neutral kaons rare decays into the pi+ pi- e+ e- final state are presented. A large CP-violating asymmetry A(K_L)=(13.9+-2.7+-2.0)% has been observed in the K_L to pi+ pi- e+ e- decay. The K_S to…
A search for the decay K_S -> pi^0mu^+mu^- has been made by the NA48/1 Collaboration at the CERN SPS accelerator. The data were collected during 2002 with a high-intensity K_S beam. Six events were found with a background expectation of…
A search for the decay Ks->pi0e+e- has been made by the NA48/1 experiment at the CERN SPS accelerator. Using data collected during 89 days in 2002 with a high-intensity Ks beam, 7 events were found with a background of 0.15 events. The…
New results on radiative K+- decays from the NA48/2 experiment are presented. In the channel K+- -> pi+- pi0 gamma more than 1 million decays were reconstructed, leading to the first measurement of the interference between direct photon…
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…
Results from recent analyses of the NA48 experiment at CERN are compared with other experiments and confronted with theoretical predictions to provide constraints on the CKM matrix and on CP Violation. The observable eta+- is related to the…
A sample of 7253 $K^\pm\to\pi^\pm e^+e^-$ decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the form factor, the branching ratio, and the…
The first observations of the rare decays KS->pi0e+e- and KS->pi0mu+mu- have been made by the NA48/1 collaboration at the CERN SPS accelerator. From high intensity KS data collected during the 2002 run, clean signals of 7 KS->pi0e+e- events…
The experimental program for the study of the rare kaon decays, K -> pnn, is summarized. A review of recent results is provided along with a discussion of prospects for the future of this program. The primary focus of the world-wide kaon…
Recent results from the NA48/1 and NA48/2 experiments at the CERN SPS are presented. NA48/2 carried out data taking in 2003 and 2004 collecting charged kaon decays: branching ratios and form factors have been measured for the rare K+- to…
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…
A large low-background sample of events (10300) has been collected for the rare decay of kaons in flight K+ -> pi+ e+ e- by experiment E865 at the Brookhaven AGS. The decay products were accepted by a broad band high-resolution charged…
Using the complete KTeV data set of 5241 candidate KL->pi+pi-e+e- decays (including an estimated background of 204+-14 events), we have measured the coupling gCR=0.163+- 0.014(stat)+-0.023(syst) of the CP conserving charge radius process…
The NA62 experiment reports an investigation of the $K^+\rightarrow\pi^+\nu\bar{\nu}$ mode from a sample of $K^+$ decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of $(0.389\pm…
The decay rate of the neutral long-lived K meson into the e+ e- e+ e- final state has been measured with the NA48 detector at the CERN SPS. Using data collected in 1999, a total of 132 events has been observed with negligible background.…
The NA48/2 Collaboration at CERN has accumulated and analysed unprecedented statistics of rare kaon decays in the $K_{e4}$ modes: $K_{e4}(+-)$ ($K^\pm \to \pi^+ \pi^- e^\pm \nu$) and $K_{e4}(00)$ ($K^\pm \to \pi^0 \pi^0 e^\pm \nu$) with…
Rare Kaon decays and CP violation are important tools to test the Standard Model and its extensions. We describe kaon physics observables testing CP violation and more generally short distance physics. Channels under consideration will be K…
More than 400 $K^{+}\to\pi^{+}\mu^+\mu^-$ events were observed in a rare $K^+$ decay experiment at the AGS. Normalized to the $K^{+}\to\pi^{+}\pi^+\pi^-$ decay, the branching ratio is determined to be $(9.22 \pm 0.60 (stat) \pm 0.49…
Measured ratios of decay rates for Ke3/K2\pi, K\mu3/K2\pi and K\mu3/Ke3 are presented. These measurements are based on K^+- decays collected in a dedicated run in 2003 by the NA48/2 experiment at CERN. The results obtained are Ke3/K2\pi =…