Search for the lepton number violation decay $\ddot{I}‰\to \ddot{I}{€}^{+}\ddot{I}{€}^{+}{e}^{-}{e}^{-}+c.c.$

Abstract

The lepton number violation decay $\ddot{I}‰\to \ddot{I}{€}^{+}\ddot{I}{€}^{+}{e}^{-}{e}^{-}+c.c.$ is searched for via $J/\ddot{I}ˆ\to \ddot{I}‰\hat{I}\cdot$ using a data sample of $(1.0087\pm 0.0044)\times 10^{10}$ $J/\ddot{I}ˆ$ events collected by the BESIII detector at the BEPCII collider. No significant signal is observed, and the upper limit on the branching fraction of $\ddot{I}‰\to \ddot{I}{€}^{+}\ddot{I}{€}^{+}{e}^{-}{e}^{-}+c.c.$ at the 90\% confidence level is determined for the first time to be $2.8\times 10^{-6}$.

9 pages, 3 figures