# Search for rare decay $J/\psi \to \varphi {e}^{+}{e}^{-}$

26 March 2019

Abstract: Using a data sample of $448.1×{10}^{6}\text{}\text{}\psi \left(3686\right)$ events collected at $\sqrt{s}=3.686\text{}\text{}\mathrm{GeV}$ with the BESIII detector at the Beijing Electron-Positron Collider II, we search for the rare decay $J/\psi \to \varphi {e}^{+}{e}^{-}$ via $\psi \left(3686\right)\to {\pi }^{+}{\pi }^{-}J/\psi$. No signal events are observed and the upper limit on the branching fraction is set to be $B\left(J/\psi \to \varphi {e}^{+}{e}^{-}\right)<1.2×{10}^{-7}$ at the 90% confidence level, which is still about one order of magnitude higher than the Standard Model prediction.

Published in: Physical Review D 99 (2019)