We report on the first search for electron-muon flavor violation in the decay of a b quark and anti-b quark bound state. A search for the LFV decay Υ(3S) → e± μ∓ in a sample of 118 million Υ(3S) mesons from 27 fb−1 of data collected with the BABAR detector at the SLAC PEP-II e+e− collider operating with a 10.36 GeV center-of-mass energy revealed no signal. We set a limit on the branching fraction B(Υ(3S) → e± μ∓) < 3.6×10^−7 at 90% CL. This can be interpreted as a limit on the energy scale divided by coupling of relevant new physics (NP) processes of Λ_NP/g_NP^2 > 80 TeV.
|What is your topic?||Lepton universality and flavour violation|