Search for rare decay J/ψ→ϕe+e−

Abstract

Using a data sample of 448.1 × 10 6 ψð3686Þ events collected at ffiffi ffi s p ¼ 3.686 GeV with the BESIII detector at the Beijing Electron-Positron Collider II, we search for the rare decay J=ψ → ϕe þ e − via ψð3686Þ → π þ π − J=ψ. No signal events are observed and the upper limit on the branching fraction is set to be BðJ=ψ → ϕe þ e − Þ < 1.2 × 10 −7 at the 90% confidence level, which is still about one order of magnitude higher than the Standard Model prediction.