Manifestation of near-threshold $Λ\barΛ$ resonances in $e^{+}e^{-}\rightarrowΛ\barΛη$ process

Abstract

It is shown that the invariant-mass distribution of $Λ\barΛ$ pairs in the process $e^{+}e^{-}\rightarrowΛ\barΛη$ can be explained by near-threshold resonances with quantum numbers $J^{PC}=1^{--}$ and $J^{PC}=1^{+-}$. The resonance with $J^{PC}=1^{--}$ corresponds to a loosely bound state, while the resonance with $J^{PC}=1^{+-}$ is a virtual state above the threshold. Accounting for both resonances results in good agreement between theoretical predictions and experimental data. The predicted angular distribution of $η$ mesons is also consistent with experimental data. It is shown that in our model there is a strong dependence of $η$-meson angular distribution on the invariant mass of $Λ\barΛ$ pair.