Related papers: First search for $K^+\to\pi^0\pi\mu e$ decays

We present a search for lepton-flavor-violating tau decays into three leptons (electrons or muons) using 782 fb^-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. No evidence for these decays is…

We present the results of a search for charged-lepton-flavor violating decays $\tau^{-} \rightarrow \ell^{-}K_{S}^{0}$, where $\ell^{-}$ is either an electron or a muon. We combine $e^+e^-$ data samples recorded by the Belle II experiment…

A sample of $1.3 \times 10^5$ $K^+ \to \pi^0 e^+ \nu \gamma$ candidates with less than 1% background was collected by the NA62 experiment at the CERN SPS in 2017-2018. Branching fraction measurements are obtained at percent relative…

A search for the charged lepton flavor violating decay $J/\psi\to e^{\pm}\tau^{\mp}$ with $\tau^{\mp} \to \pi^{\mp}\pi^0\nu_{\tau}$ is performed with about $10$ billion $J/ \psi$ events collected with the BESIII detector at the BEPCII. No…

The NA62 experiment at the CERN SPS aims to measure the branching ratio of the rare decay $K^+\to\pi^+\nu\bar\nu$ with a relative precision of $\sim10%$. To achieve that goal, it is designed to be exposed to $1.2\times 10^{13}$ $K^+$ decays…

We consider a process $K_{L e5} ( K_{L} \rightarrow \pi^{0} \pi^{0} \pi^{\pm} e^{\mp} \nu )$ as a standard model background to the experiment $K_{L} \rightarrow \pi^{0} \mu^{\pm} e^{\mp}$, which seeks for possible violation of lepton family…

We perform the first search for lepton-number-violating B+->D-l+l'+ decays, where l and l' stand for e or mu, using 772 x 10^6 BB-bar pairs accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+e^- collider. No…

A search for the lepton-flavour violating decays $B^0_s \rightarrow e^\pm \mu^\mp$ and $B^0 \rightarrow e^\pm \mu^\mp$ is performed based on a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb$^{-1}$,…

We search for the flavor-changing neutral current decays D0\to mu+mu- and D0\to e+e-, and for the lepton-flavor violating decays D0\to e\pm mu\mp using 660 fb^-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e-…

Using $(1.0087\pm0.0044)\times10^{10}$ $J/\psi$ events collected by the BESIII detector at the BEPCII collider, we search for the lepton number violation decay $\phi \to \pi^+ \pi^+ e^- e^-$ via $J/\psi\to \phi\eta$. No signal is found and…

We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\to\mu^+\mu^-$, and the lepton-flavor violating decay $\Dz\to e^\pm\mu^\mp$. The measurement is based on $122 {fb}^{-1}$ of data collected by the…

Using a sample of 12.2 million $\tau$-lepton pairs produced by $e^+e^-$ annihilation at $\sqrt{s}\sim 10.6 $GeV and collected by the CLEO detector, we search for and set limits on CP violation in $\tau$-lepton decays. For each event, we…

The analysis of a combined data set, totaling 3.6 \times 10^14 stopped muons on target, in the search for the lepton flavour violating decay mu^+ -> e^+ gamma is presented. The data collected by the MEG experiment at the Paul Scherrer…

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…

We present a search for the lepton flavor violating decay $J/\psi\to e^{\pm}\mu^{\mp}$ using $8.998\times 10^{9} J/\psi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ storage ring. No excess of signal above background is…

A search for the lepton-flavour violating decay $D^0 \to e^\pm \mu^\mp$ is made with a dataset corresponding to an integrated luminosity of 3.0 fb$^{-1}$ of proton-proton collisions at centre-of-mass energies of $7$ TeV and $8$ TeV,…

We have searched for the lepton-number violating processes B+ -> h- l+ l+ with h- = K-/pi- and l+ = e+/mu+, using a sample of 471+/-3 million BBbar events collected with the BaBar detector at the PEP-II e+e- collider at the SLAC National…

Using a sample of 5.8X10E7 J/$\psi$ events, the Beijing Spectrometer experiment has searched for the decay J/$\psi \to e\mu$. Four candidates, consistent with the estimated background, are observed, and an upper limit on the branching…

We have searched a sample of 9.6 million BB-bar events for the lepton-flavor-violating decays B --> h e^{+-} mu^{-+}, B^+ --> h^- e^+ e^+, B^+ --> h^- e^+ mu^+, and B^+ --> h^- mu^+ mu^+, where h is pi, K, rho, and K*(892), a total of…

We report on a search for eleven lepton-number violating processes B+ -> X- l+ l'+ with X- = K-, pi-, rho-, K*- or D- and l+/l'+ = e+ or mu+, using a sample of 471+/-3 million BBbar events collected with the BaBar detector at the PEP-II…