Search for the baryon and lepton number violating decay $ J/\psi \to p{e}^{-}+\mathrm{c}.\mathrm{c}.$

Based on $ (2712.4\pm 14.3)\times {10}^{6}\text{}\text{}\psi (3686)$ events collected by the BESIII detector operating at the BEPCII storage ring, we perform a search for the baryon- and lepton-number violating decay $ J/\psi \to p{e}^{-}+\mathrm{c}.\mathrm{c}.$ via $ \psi (3686)\to {\pi }^{+}{\pi }^{-}J/\psi $. No significant signal is found. An upper limit on the branching fraction of $ \mathcal{B}(J/\psi \to p{e}^{-}+\mathrm{c}.\mathrm{c}.)$ is found to be $ 3.1\times {10}^{-8}$ at 90% confidence level.