Role of $Ξ(1690)$ in the $J/ψ\toΞ^0\barΛK^0$ reaction

Abstract

Motivated by the recent BESIII measurements of the $J/ψ\to Ξ^0 \barΛK_S^0 + c.c.$ process, we investigate this reaction by considering the contributions from the $Ξ(1690)$ and $Λ(1890)$ resonances. The $Ξ(1690)$ state is dynamically generated from the $S$-wave pseudoscalar meson-octet baryon interactions within the chiral unitary approach. Our theoretical model provides a good description of the $\barΛK^0$, $Ξ^0 K^0$, and $\barΛΞ^0$ invariant mass distributions. The results indicate that the $Ξ(1690)$ resonance, which was neglected in the experimental analysis by BESIII, plays a crucial role in this process. Furthermore, we evaluate the theoretical uncertainties of our model using the parametric bootstrap method. Future high-precision measurements of this process will further help to elucidate the properties of the $Ξ(1690)$ and $Λ(1890)$ states.

Figures (5)

• Figure 1: Mechanisms for tree level $J/\psi\to\Xi^0 \bar{\Lambda} K^0$ and rescattering of intermediate components.
• Figure 2: Mechanism for intermediate state $\Lambda(1890)$.
• Figure 3: Invariant mass distributions of $\bar{\Lambda}K^0$ (a), $\Xi^0K^0$ (b), and $\bar{\Lambda}\Xi^0$ (c) compared with the BESIII experimental data BESIII:2025lyc.
• Figure 4: Invariant mass distributions of $\bar{\Lambda}K^0$ (a), $\Xi^0K^0$ (b), and $\bar{\Lambda}\Xi^0$ (c) compared with the BESIII experimental data BESIII:2025lyc, obtained from the improved 4-parameter fit which includes the interference phase $\phi$.
• Figure 5: Theoretical uncertainties for the invariant mass distributions of $\bar{\Lambda}K^0$ (a), $\Xi^0K^0$ (b), and $\bar{\Lambda}\Xi^0$ (c) evaluated using the parametric bootstrap method.