Search for rare decay $J/ ψ\to ϕe^+ e^-$

Abstract

Using a data sample of $448.1\times10^6$ $ψ(3686)$ events collected at $\sqrt{s}=$ 3.686 GeV with the BESIII detector at the BEPCII, we search for the rare decay $J/ψ\to ϕe^+ e^-$ via $ψ(3686) \to π^+π^- J/ψ$. No signal events are observed and the upper limit on the branching fraction is set to be $\mathcal{B}(J/ψ\to ϕe^+ e^-) < 1.2 \times 10^{-7}$ at the 90\% confidence level, which is still about one order of magnitude higher than the Standard Model prediction.

7 pages, 3 figures