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

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