Invariant-mass spectrum of $\Lambda \bar{\Lambda }$ pair in the process $e^{+}{e}^{-}\to \varphi \Lambda \bar{\Lambda }$

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 $e^{+}{e}^{-}\to \varphi \Lambda \bar{\Lambda }$. 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 $J^{PC}=2^{-+}$.

Comments: 3 pages, 1 figure