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

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