# Observation of the decay $\chi_{cJ} \to \Omega^- \bar{\Omega}^+$

## TL;DR

This paper reports the first observation of the decay of $oldsymbol{ ext{chi}_cJ}$ mesons into $oldsymbol{ ext{Omega}^- ar{ ext{Omega}}^+}$ pairs, measuring their branching fractions with high statistical significance using BESIII data.

## Contribution

First observation of $ ext{chi}_cJ o ext{Omega}^- ar{ ext{Omega}}^+$ decays and measurement of their branching fractions.

## Key findings

- Branching fractions measured for $ ext{chi}_c0$, $ ext{chi}_c1$, $ ext{chi}_c2$ decays.
- Significance levels of 5.6σ, 6.4σ, and 18σ for the three decay modes.
- First experimental evidence of these decay channels.

## Abstract

Using an $e^+e^-$ collision data sample of $(27.08 \pm 0.14) \times 10^{8}$ $\psi(3686)$ events collected by the BESIII detector, we report the first observation of $\chi_{cJ} \to \Omega^- \bar{\Omega}^+$ ($J=0,\,1,\,2$) decays with significances of $5.6\sigma$, $6.4\sigma$, and $18\sigma$, respectively, where the $\chi_{cJ}$ mesons are produced in the radiative $\psi(3686)$ decays. The branching fractions are determined to be $\mathcal{B}(\chi_{c0} \to \Omega^- \bar{\Omega}^+) = (3.51 \pm 0.54 \pm 0.29) \times 10^{-5}$, $\mathcal{B}(\chi_{c1} \to \Omega^- \bar{\Omega}^+) = (1.49 \pm 0.23 \pm 0.10) \times 10^{-5}$, and $\mathcal{B}(\chi_{c2} \to \Omega^- \bar{\Omega}^+) = (4.52 \pm 0.24 \pm 0.18) \times 10^{-5}$, where the first and second uncertainties are statistical and systematic, respectively.