Related papers: Results from the NA62 2014 Commissioning Run
We have investigated the exclusive, radiative B-meson decay to K_2^*(1430) in 88.5 * 10^6 BBbar events. We present a preliminary measurement of the branching fractions BR(B->K^*_2(1430)^0 gamma) = (1.22+-0.25+-0.11) * 10^{-5} and…
The PEN Collaboration is conducting a new measurement of the pi+ -> e+ nu branching ratio at the Paul Scherrer Institute, with the goal uncertainty of delta B/B(pie2)=5E-4 or lower. At present, the combined accuracy of all published pie2…
The NA62 experiment recorded a large sample of $K^+ \rightarrow \mu^+ \nu_{\mu}$ decays in 2007. A peak search has been performed in the reconstructed missing mass spectrum. In the absence of a signal, limits in the range $2 \times 10^{-6}$…
Based on $(448.1 \pm 2.9 )\times 10^6$ $\psi(3686)$ events collected with the BESIII detector operating at the BEPCII collider, the decay $\psi(3686)\rightarrow \phi K_{S}^{0} K_{S}^{0}$ is observed for the first time. Taking the…
In this short presentation I emphasize the increased importance of kaon flavour physics in the search for new physics (NP) that we should witness in the rest of this decade and in the next decade. The main actors will be the branching…
Branching fraction and asymmetry measurements of charmless $B^+\to K^{*+}h^+_1h^-_2$ (where $h_{1,2}$ = $K$, $\pi$) decays are presented, using a data sample of 232 million $\Upsilon(4S) \to$ $BB$ decays collected with the BaBar detector at…
We present a measurement of the branching fraction for the decay B^0->a1+(1260)pi- with a1+->pi+pi+pi- using a data sample containing 535x10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider…
We have investigated the exclusive, radiative B meson decays to K2*(1430) in 89* 10^6 BBbar events with the BaBar detector at the PEP-II storage ring. We measure the branching fractions BR(B0 -> K2*(1430)0 gamma) = (1.22 +-0.25…
A search for the decay $K_S\to\pi^0\gamma\gamma$ has been made using the NA48 detector at the CERN SPS. Using data collected in 1999 during a 40-hour run with a high-intensity $K_S$ beam, an upper limit for the branching ratio…
We summarize the recent strategy for an efficient hunting of new animalcula with the help of rare K and B decays that avoids the use of the $V_{cb}$ and $V_{ub}$ parameters that are subject to tensions between their determinations from…
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…
A measurement of the decay K+ -> pi0 mu+ nu_mu gamma has been performed with the E787 detector at Brookhaven National Laboratory. Forty events were observed in the signal region with the background expectation of (16.5 +- 2.7) events. The…
Precise measurements of the branching ratios for the flavor-changing neutral current decays $K\to\pi\nu\bar{\nu}$ can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. It is important to measure both…
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…
A sample of kinematically identified $K^+ \to \pi^+ \pi^0$ decays obtained with the E949 detector was used to search for the helicity-suppressed decay $\pi^0 \to \nu \bar{\nu}$ resulting in an upper limit of $2.7\times10^{-7}$ at 90%…
We report experimental details and results of a new measurement of the decay K+ -> pi+pi-e+nue (Ke4}. A sample of more than 400,000 Ke4 events with low background has been collected by Experiment 865 at the Brookhaven Alternate Gradient…
The experiment E865 at BNL places an upper limit on the branching ratio for the decay K+ -> pi+ mu+ e- of 3.9x10^-11 (90% C.L.). Along with with other results this yields a combined upper limit on this branching ratio of 2.8x10^-11. A new…
The rare kaon decay $K_L\to\pi^0\nu\bar{\nu}$ is extremely sensitive to new physics, because the contribution to this decay in the Standard Model (SM) is highly suppressed and known very accurately; the branching ratio is $3\times 10^{-11}$…
A search for heavy neutral lepton production in $K^+$ decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the $10^{-7}$ to $10^{-6}$ level are established on…
The ratio R_K=Gamma(Ke2)/Gamma(Kmu2) provides a very powerful probe for the weak interactions structure. This ratio of decay rates is calculated with very high precision within the Standard Model but the corrections due to the presence of…