Search for the lepton number violation decay $\omega \to {\pi }^{+}{\pi }^{+}{e}^{-}{e}^{-}+c\mathrm{.}c\mathrm{.}$

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