Related papers: A limit for the mu -> e gamma decay from the MEG e…
Based on a sample of \etapr mesons produced in the radiative decay $J/\psi\to\gamma\eta^{\prime}$ in $1.31\times 10^9$ $J/\psi$ events collected with the BESIII detector, the decay $\eta^{\prime}\to\omega e^{+} e^{-}$ is observed for the…
A search for the Bs->mumu and Bd->mumu decays is performed in ~300 pb-1 of pp collisions at sqrt(s) = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The measured limit on the branching fraction of the Bs->mumu…
A search for the exclusive radiative decays B --> rho(770) gamma and B0 --> omega(782) gamma is performed on a sample of about 84\times 10^{6} B\bar B events collected by the BaBar detector at the PEP-II asymmetric-energy e+e- storage ring.…
The most sensitive experiment to date to search for the muon and electron lepton number violating decay $K^0_L \to \mu^\pm e^\mp$ has detected no events consistent with this process. Based on this result, the 90% confidence level upper…
We have performed a search for the angular-momentum forbidden decay K+ -> pi+ gamma with the E787 detector at BNL. No events were observed in the pi+ kinematic region around 227 MeV/c. An upper limit on the branching ratio for the decay is…
The MEG Experiment searches for a lepton flavour violating decay, $\mu^+\to\mathrm{e}^+\gamma $, with a branching-ratio sensitivity of $10^{-13}$ in order to explore the parameter region predicted by many theoretical models beyond the…
A search for the $K^+\to\mu^-\nu e^+e^+$ decay, forbidden within the Standard Model by either lepton number or lepton flavour conservation depending on the flavour of the emitted neutrino, has been performed using the dataset collected by…
Using a data sample of $(10087 \pm 44) \times {10^{6}}$ $J/{\psi}$ events collected with the BESIII detector, we search for the decays $\eta/\eta'\to e^+e^-\mu^+\mu^-$ and $\eta' \to \mu^+\mu^-\mu^+\mu^-$ via the radiative decays…
We present a new measurement of the branching ratio of the decay K_L -> pi e nu gamma (Ke3g) with respect to K_L -> pi e nu (Ke3), and the first study of the photon energy spectrum in this decay. We find BR(Ke3g, E*g>30 MeV, theta*_eg>20…
Measurements of branching fractions for nine different final states, based on a data sample of approximately 4 million psi(2S) events collected with the BESI detector at the BEPC, are reported. Using the same event sample, radiative decays…
We search for the decay B+ -> l+ nu gamma with l+ = e+ or mu+ using the full Belle data set of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one…
We present a search for the radiative leptonic decays B+ -> e+ nu gamma and B+ -> mu+ nu gamma using data collected by the BABAR detector at the PEP-II B factory. We fully reconstruct the hadronic decay of one of the B mesons in Upsilon(4S)…
The KARMEN collaboration has reported the possible observation of a hitherto unknown neutral and weakly interacting particle x, which is produced in the decay pi -> mu + x with a mass m(x) = 33.9 MeV. We have searched for this hypothetical…
A blind analysis searching for the decay Bs0 -> mumu has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. With an integrated luminosity of 2.4 fb^(-1) no excess…
An improved measurement of the decay $B^0_s\to\mu^+\mu^-$ and searches for the decays $B^0\to\mu^+\mu^-$ and $B^0_s\to\mu^+\mu^-\gamma$ are performed at the LHCb experiment using data collected in proton-proton collisions at $\sqrt{s} =…
The cross section of the process e+ e- --> pi0 pi0 gamma has been measured in the c.m. energy range 600--970 MeV with the CMD-2 detector. The following branching ratios have been determined: B(rho --> pi0 pi0 gamma) =(5.2^{+1.5}_{-1.3} +-…
The Standard Model predicts a branching ratio for the decay mode Bs -> mu mu of (3.4 +/- 0.5)10e-9, while some SUSY models predict enhancements up to 2 orders of magnitude. It is expected that at the end of its life Tevatron will set and…
We report on results of a search for the decay mode K_L -> pi^0 gamma e^+ e^- conducted by the E162 experiment at KEK. We observed no events and set a 90% confidence level upper limit of Br(K_L -> pi^0 gamma e^+ e^-)< 7.1x10^{-7} for its…
The MEG experiment took data at the Paul Scherrer Institute in the years 2009--2013 to test the violation of the lepton flavour conservation law, which originates from an accidental symmetry that the Standard Model of elementary particle…
With the BaBar detector at the PEP-II asymmetric $B$ Factory at SLAC, we present the first search for the decays $B^0\to\ell^+\ell^-\gamma$ ($l=e, \mu$). Using a data set of 292 $fb^{-1}$ collected at the $\Upsilon(4S)$ resonance, we find…