Search for the lepton number violating decay $\hat{I}\cdot \to \ddot{I}{€}^{+}\ddot{I}{€}^{+}{e}^{-}{e}^{-}+c.c.$ via $J/\ddot{I}ˆ\to \ddot{I}•\hat{I}\cdot$

Abstract

Based on a sample of $(10.087\pm 0.044)\times 10^{9}J/\ddot{I}ˆ$ events collected by the BESIII detector at the BEPCII collider, we perform the first search for the lepton number violating decay $\hat{I}\cdot \to \ddot{I}{€}^{+}\ddot{I}{€}^{+}{e}^{-}{e}^{-}+\text{c.c.}$ No signal is found, and an upper limit on the branching fraction of $\hat{I}\cdot \to \ddot{I}{€}^{+}\ddot{I}{€}^{+}{e}^{-}{e}^{-}+c.c.$ is set to be $4.6\times 10^{-6}$ at the 90\% confidence level.

9 pages, 2 figures