Related papers: Testing mu-e universality with Kl2 decays
The ratio $R_K = \Gamma(K^{\pm}\to e^{\pm}\nu(\gamma)) / \Gamma(K^{\pm}\to\mu^{\pm}\nu(\gamma))$ provides a powerful probe of the structure of weak interactions. It is calculated with very high precision within the Standard Model, but…
The experiment NA62 at CERN collected a large sample of K+- leptonic decays in order to perform precise test of lepton universality, by measuring the helicity suppressed ratio R_K=Gamma(K+- --> e+- nu)/Gamma(K+- --> mu+- nu). The…
The NA62 experiment at CERN collected a large sample of $K^+\to e^+\nu$ decays during a dedicated run in 2007, which allows a precise test of lepton universality by measurement of the helicity suppressed ratio $R_K = \Gamma(K^+\to…
The ratio $R_K=\frac{\Gamma(K\to e \nu_{e} (\gamma))}{\Gamma(K\to \mu \nu_{\mu} (\gamma))}$ of leptonic decay rates provides a golden probe for testing the structure of the weak interactions because it can be predicted with high accuracy…
The ratio of the leptonic charged kaon decays $R_K= \Gamma(K^{\pm} \to e^{\pm}\nu) / \Gamma(K^{\pm} \to \mu^{\pm}\nu)$ is sensitive to the structure of the week interactions and can be precisely calculated within the Standard Model.…
The NA62 experiment at CERN aims to use rare kaon decays to search for new phenomena beyond the Standard Model. During the current short term phase (data taking completed in years 2007-8), the ratio $R_K = \Gamma(K^+ \rightarrow e \nu_e…
The recent NA48/2 improvement on R_K=Gamma(K->e nu_e)/Gamma(K->mu nu_mu) emphasizes the role of K_l2 decays in probing the mu-e universality. Supersymmetric (SUSY) extensions of the Standard Model can exhibit mu-e non-universal…
Rare kaon decays provide unique opportunity to test the Standard Model and probe its possible extensions. The final result on the lepton universality test by measuring the ratio R_K = G(K+- to e+- nu)/G(K+- to mu+- nu) is presented as well…
The NA62 experiment at SPS is a continuation of the long standing CERN kaon physics program. The high statistics and the unprecedent precision allow to probe the Standard Model and test the description of the strong interactions at low…
We have calculated the ratios $R_{e/\mu}^{(P)} \equiv \Gamma(P \to e \bar{\nu}_e [\gamma])/ \Gamma(P \to \mu \bar{\nu}_\mu [\gamma])$ ($P=\pi,K$) in Chiral Perturbation Theory up to $\mathcal{O}(e^2p^4)$, finding $R_{e/\mu}^{(\pi)} =…
Kaon decay studies seeking new-physics (NP) effects in leptonic (K_l2) or semileptonic (K_l3) decays are discussed. A unitarity test of the first row of the CKM mixing matrix is obtained from the KLOE precision measurements of Kl3 widths…
Recent results a future prospects of the NA62 experiment at CERN SPS are presented. The NA62 experiment performed the most precise measurement of the ratio $R_K$ of the $K^+\rightarrow e^\pm\nu$ and K^+\rightarrow \mu^\pm\nu$ decay rates…
The E36 experiment recently conducted at J-PARC by the TREK Collaboration will provide a precise mesurement of the decay ratio $ R_K = \Gamma(K^+ \rightarrow e^+\nu_e) / \Gamma(K^+ \rightarrow \mu^+\nu_{\mu}) $ with the aim of testing…
A precision test of lepton universality by measurement of the ratio RK of K-->e nu to K-->mu nu decay rates was performed using a sample of 59963 K-->e nu candidates with 8.8% background contamination collected by the CERN NA62 experiment.…
Recent results from the NA48/2 and NA62 kaon decay-in-flight experiments at CERN are presented. A precision measurement of the helicity-suppressed ratio RK of the K+- to e+- nu and K+- to mu+- nu decay rates has been performed using the…
A precision measurement of the ratio RK of the rates of kaon leptonic decays K+- --> e nu and K+- --> mu nu with the full data sample collected by the NA62 experiment at CERN in 2007-2008 is reported. The result, obtained by analysing…
Searches for lepton flavour and lepton number violation in kaon decays by the NA48/2 and NA62 experiments at CERN are presented. A precision measurement of the helicity-suppressed ratio RK of the K --> e nu and K --> mu nu decay rates has…
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.…
In the Standard Model, lepton universality refers to the identical electroweak gauge interactions among charged leptons. The measurement of the branching ratio $R_{e / \mu} = \frac{\Gamma(\pi\rightarrow\ e…
Searches for lepton flavour violation and lepton number violation in kaon decays by the NA62 and NA48/2 experiments at CERN are presented. A new measurement of the ratio of charged kaon leptonic decay rates…