Search for $ \mathrm{\Lambda }-\overline{\mathrm{\Lambda }}$ oscillation in $ J/\psi \to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}$ decay

Using $ (10087\pm 44)\times {10}^{6}\text{}\text{}J/\psi $ decays collected by the BESIII detector at the BEPCII collider, we search for baryon number violation via $ \mathrm{\Lambda }-\overline{\mathrm{\Lambda }}$ oscillation in the decay $ J/\psi \to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}$. No evidence for $ \mathrm{\Lambda }-\overline{\mathrm{\Lambda }}$ oscillation is observed. The upper limit on the time-integrated probability of $ \mathrm{\Lambda }-\overline{\mathrm{\Lambda }}$ oscillation is estimated to be $ 1.4\times {10}^{-6}$, corresponding to an oscillation parameter less than $ 2.1\times {10}^{-18}\text{}\text{}\mathrm{GeV}$ at 90% confidence level.