Related papers: A New Upper Limit on the Decay $\eta\to e^{+}e^{-}…
The first search for ultra-rare $K^+$ decays into the $\pi^+e^+e^-e^+e^-$ final state is reported, using a dataset collected by the NA62 experiment at CERN in 2017-2018. An upper limit of $1.4\times 10^{-8}$ at 90% CL is obtained for the…
Based on $(27.12\pm 0.14)\times 10^{8}$ $\psi(2S)$ events collected with the BESIII detector, we search for the decay $\eta_c (2S) \rightarrow \pi^{+} \pi^{-} \eta_c$ with $\eta_c\rightarrow K_S^0 K^{\pm}\pi^{\mp}$ and $\eta_c\rightarrow…
A search for the decay mu -> e gamma, performed at PSI and based on data from the initial three months of operation of the MEG experiment, yields an upper limit on the branching ratio of BR(mu -> e gamma) < 2.8 x 10**-11 (90% C.L.). This…
Using the angular correlation between the $\pi^+$ emitted in a $D^{*+} \rightarrow D^0 \pi^+$ decay and the $e^+$ emitted in the subsequent $D^0 \rightarrow Xe^+\nu$ decay, we have measured the branching fraction for the inclusive…
Using a data sample with integrated luminosity of about 3.9 fb^{-1} collected in e+ e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds -> (eta, eta')…
Using a data sample of $(1310.6 \pm 7.0)\times 10^6$ $J/\psi$ events collected with the BESIII detector operating at the BEPCII collider, we perform the first experimental search for invisible decays of a light vector meson…
A search for the rare decay $\eta \rightarrow e^+e^-$ is performed using the inverse process $e^+e^- \rightarrow \eta$ in the decay mode $\eta\to\pi^0\pi^0\pi^0 $. We analyze data with an integrated luminosity of 654 nb$^{-1} $ accumulated…
We present the results of searches for B decays to charmless two-body final states containing $\eta^\prime$ or $\omega$ mesons, based on 20.7 fb$^{-1}$ of data collected with the BABAR detector. We find the branching fractions ${\cal…
We report the first observation of $B_s^0\to J/\psi\eta$ and evidence for $B_s^0\to J/\psi\eta'$. These results are obtained from $23.6 \mathrm{fb}^{-1}$ of data collected at the $\Upsilon(5S)$ resonance with the Belle detector at the KEKB…
We have searched for lepton-flavor-violating $\tau$ decays with a pseudoscalar meson ($\eta$, $\eta'$ {and} $\pi^0$) using a data sample of 401 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No…
We present measurements of the branching fractions and charge asymmetries (where appropriate) of two-body B decays to eta(')K*, eta(')rho, eta(')pi0, omegapi0, and phipi0. The data were recorded with the BABAR detector at PEP-II and…
The cross sections of the $e^{+}e^{-}\to\phi\eta'$ process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb$^{-1}$ data collected with the BESIII detector operating at the BEPCII storage…
Using $(10.087\pm0.044)\times10^{9}$ $J/\psi$ events collected by the BESIII detector at the BEPCII collider, we search for the hyperon semileptonic decay $\Xi^{-} \rightarrow \Xi^{0} e^{-} \bar{\nu}_{e}$. No significant signal is observed…
Using a data sample of $(448.1\pm2.9)\times10^{6}$ $\psi(3686)$ decays collected by the BESIII detector at the Beijing Electron Positron Collider (BEPCII), we observe the decays $\chi_{cJ}\to \phi\phi\eta~(J=0,~1,~2)$, where the $\chi_{cJ}$…
Using $10.1\times10^{9}$ $J/\psi$ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy $\sqrt{s}=3.097~\rm{GeV}$ and collected with the BESIII detector, we present a search for the rare semi-leptonic…
We present the first upper-limit measurement of the branching fractions of the isospin-violating transitions $\chi_{c0,2} \rightarrow \pi^{0} \eta_{c}$. The measurements are performed using $106\times 10^{6}$ $\psi(3686)$ events accumulated…
Using data recorded by the CLEO III detector at CESR, we report on the first measurements of the branching fractions for decays of the Lambda_c^+ charmed baryon into (Lambda pi+ pi+ pi- pi0) and (Lambda omega pi+). All rates are measured…
A search for the rare $\eta$ $\to$ $\mu^+\mu^-\mu^+\mu^-$ double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers in 2017-2018 and…
We present the first search for the semileptonic decay $D_s^+\to \pi^0 e^+\nu_e$ using a data sample of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.178 and 4.226~GeV, corresponding to…
We present measurements of the B->eta K gamma branching fractions and upper limits for the B->eta' K gamma branching fractions. For B->eta K+ gamma we also measure the time-integrated charge asymmetry. The data sample, collected with the…