Search For High Mass Resonances Decaying Into Leptons Of Different Flavor E Mu E Tau Mu Tau In P Anti P Collisions At Sqrts

We present a search for high-mass resonances decaying into two leptons of different flavor: e[mu], e[tau], and [mu][tau]. These resonances are predicted by several models beyond the standard model, such as the R-parity-violating MSSM. The search is based on 1 fb−1 of data collected at the Collider Detector at Fermilab (CDF II) in proton anti-proton collisions. Our observations are consistent with the standard model expectations. The results are interpreted to set 95% C.L. upper limits on [sigma] x BR of {tilde {nu}}{sub [tau]} → e[mu], e[tau], [mu]{tau}.

We present a search for high-mass resonances decaying into two leptons of different flavor: e?, e ?, ??. These resonances are predicted by several models beyond the standard model, such as the R-parity-violating MSSM. The search is based on 1 fb-1 of data collected at the Collider Detector at Fermilab (CDF II) in proton anti-proton collisions. Our observations are consistent with the standard model expectations. The results are interpreted to set 95% C.L. upper limits on ? x BR of $ ilde{v}$? → e?, e ?, ??.

A direct search for lepton flavour violating decays of the Higgs boson (H) in the H to e tau and H to e mu channels is described. The data sample used in the search was collected in proton-proton collisions at sqrt(s)=8 TeV with the CMS detector at the LHC and corresponds to an integrated luminosity of 19.7 inverse femtobarns. No evidence is found for lepton flavour violating decays in either final state. Upper limits on the branching fractions, B(H to e tau)

Searches for lepton-flavor-violating decays of a [tau] lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 ± 7) x 106 [tau] decays collected by the BABAR detector near the [Upsilon](4S), [Upsilon](3S) and [Upsilon](2S) resonances. The searches yield no evidence of signals and they set upper limits on the branching fractions of [Beta]([tau]{sup {+-}} 2!e{sup {+-}}[gamma])

We describe a general search for resonances decaying to a neutral e{mu} final state in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. Using a data sample representing 344 pb{sup -1} of integrated luminosity recorded by the CDF II experiment, we compare Standard Model predictions with the number of observed events for invariant masses between 50 and 800 GeV/c{sup 2}. Finding no significant excess (5 events observed vs. 7.7 {+-} 0.8 expected for M{sub e{mu}}> 100 GeV/c{sup 2}), we set limits on sneutrino and Z' masses as functions of lepton family number violating couplings.

Searches for lepton-flavor-violating decays of a? lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 ± 7) x 106? decays collected by the BABAR detector near the?(4S),?(3S) and?(2S) resonances. The searches yield no evidence of signals and they set upper limits on the branching fractions of?(?{sup {+-}} → e{sup {+-}}?)

We use the ATLAS detector at the Large Hadron Collider to search for the lepton flavor violating process Z→e[mu] in pp collisions using 20.3 fb-1 of data collected at √s=8 TeV. An enhancement in the e[mu] invariant mass spectrum is searched for at the Z-boson mass. The number of Z bosons produced in the data sample is estimated using events of similar topology, Z→ee and [mu][mu], significantly reducing the systematic uncertainty in the measurement. In conclusion, there is no evidence of an enhancement at the Z-boson mass, resulting in an upper limit on the branching fraction, B(Z→e[mu])

A search for narrow resonances decaying to an electron and a muon is presented. The $mathrm {e}$ ${mu }$ mass spectrum is also investigated for non-resonant contributions from the production of quantum black holes (QBHs). The analysis is performed using data corresponding to an integrated luminosity of 19.7 $̃text {fb}̂text {-1}$ collected in proton-proton collisions at a centre-of-mass energy of 8 $̃text {TeV}$ with the CMS detector at the LHC. With no evidence for physics beyond the standard model in the invariant mass spectrum of selected $mathrm {e}mu $ pairs, upper limits are set at 95 $%$ confidence level on the product of cross section and branching fraction for signals arising in theories with charged lepton flavour violation. In the search for narrow resonances, the resonant production of a $mathrm { au }$ sneutrino in R-parity violating supersymmetry is considered. The $mathrm { au }$ sneutrino is excluded for masses below 1.28 $̃text {TeV}$ for couplings $lambda _„=lambda _ç=lambda '_ķ=0.01$ , and below 2.30 $̃text {TeV}$ for $lambda _„=lambda _ç=0.07$ and $lambda '_ķ=0.11$ . These are the most stringent limits to date from direct searches at high-energy colliders. In addition, the resonance searches are interpreted in terms of a model with heavy partners of the ${mathrm {Z}} $ boson and the photon. In a framework of TeV-scale quantum gravity based on a renormalization of Newton’s constant, the search for non-resonant contributions to the $mathrm {e}$ ${mu }$ mass spectrum excludes QBH production below a threshold mass $M_{mathrm {th}}$ of 1.99 $̃text {TeV}$ . In models that invoke extra dimensions, the bounds range from 2.36 $̃text {TeV}$ for one extra dimension to 3.63 $̃text {TeV}$ for six extra dimensions. Furthermore, this is the first search for QBHs decaying into the $mathrm {e}$ ${mu }$ final state.

This Letter presents a search for a heavy neutral particle decaying into an opposite-sign different-flavor dilepton pair, e±?∓, e±?∓, or ?±?∓ using 20.3 fb-1 of pp collision data at √s=8 TeV collected by the ATLAS detector at the LHC. The numbers of observed candidate events are compatible with the standard model expectations. Limits are set on the cross section of new phenomena in two scenarios: the production of ????????? in R-parity-violating supersymmetric models and the production of a lepton-flavor-violating Z' vector boson.