Search for rare decay J /? ??e+e-

Abstract

Using a data sample of 448.1×106 ?(3686) events collected at s=3.686 GeV with the BESIII detector at the Beijing Electron-Positron Collider II, we search for the rare decay J/???e+e- via ?(3686)??+?-J/?. No signal events are observed and the upper limit on the branching fraction is set to be B(J/???e+e-)<1.2×10-7 at the 90% confidence level, which is still about one order of magnitude higher than the Standard Model prediction. © 2019 authors. Published by the American Physical Society.