Invariant-mass spectrum of $\Lambda\bar\Lambda$ pair in the process $e^+e^-\rightarrow\phi\Lambda\bar\Lambda$

Abstract

We show that the final-state interaction perfectly explains the recent experimental data of BESIII Collaboration on the near-threshold invariant-mass spectrum of $\Lambda\bar\Lambda$ in the process $e^+e^-\rightarrow\phi\Lambda\bar\Lambda$. The position of peak in invariant-mass spectrum is above the threshold though the interaction of $\Lambda$ and $\bar\Lambda$ is due to an attractive potential. This potential has a simple form and depends only on two parameters. We show that the invariant-mass spectrum is consistent with the quantum numbers $J^{PC}=1^{++}$ and $2^{++}$ of $\Lambda\bar\Lambda$ pair but contradicts to $J^{PC}=2^{-+}$.