Search for baryon and lepton number violation in $J/\psi \to {\Lambda }_{c}^{+}{e}^{-}+c.c.$

Using $1.31×1{0}^{9}$ $J/\psi $ events collected by the BESIII detector at the Beijing Electron Positron Collider, we search for the process $J/\psi \to {\Lambda }_{c}^{+}{e}^{-}+c.c.$ for the first time. In this process, both baryon and lepton number conservation is violated. No signal is found and the upper limit on the branching fraction $B\left(J/\psi \to {\Lambda }_{c}^{+}{e}^{-}+c.c.\right)$ is set to be $6.9×1{0}^{-8}$ at the 90% confidence level.