Search for \(\bar{\Lambda}\)-\(\Lambda\) oscillations in the decay \(J/\psi \to p K^- \bar{\Lambda}+c.c.\)

We report the first search for \(\bar\Lambda\)--\(\Lambda\) oscillations in the decay \(J/\psi \to p K^- \bar{\Lambda} + c.c.\) by analyzing \(1.31\times10^9\) \(J/\psi\) events accumulated with the BESIII detector at the BEPCII collider. The \(J/\psi\) events are produced using \(e^+e^-\) collisions at a center of mass energy \(\sqrt{s}= 3.097\)~GeV. No evidence for hyperon oscillations is observed. The upper limit for the oscillation rate of \(\bar\Lambda\) to \(\Lambda\) hyperons is determined to be \(\mathcal{P}(\Lambda)=\frac{\mathcal{B}(J/\psi\to pK^-\Lambda+c.c.)}{\mathcal{B}(J/\psi\to pK^-\bar\Lambda+c.c.)}