Observation of $\chi_{c0}\to\Sigma^{+}\bar{\Sigma}^{-}\eta$ and evidence for $\chi_{c1,2}\to\Sigma^{+}\bar{\Sigma}^{-}\eta$

TL;DR

This paper reports the first observation of the decay $oldsymbol{ ext{chi}_c0 o ext{Sigma}^+ ar{ ext{Sigma}}^- ext{eta}}$ and evidence for similar decays of $oldsymbol{ ext{chi}_c1}$ and $oldsymbol{ ext{chi}_c2}$, providing new measurements of their branching fractions.

Contribution

First observation of $ ext{chi}_c0$ decay to $ ext{Sigma}^+ ar{ ext{Sigma}}^- ext{eta}$ and evidence for $ ext{chi}_c1$ and $ ext{chi}_c2$ decays, with measured branching fractions.

Findings

First decay observation with 7.0σ significance.

Measured branching fractions for $ ext{chi}_c$ decays.

Evidence for $ ext{chi}_c1$ and $ ext{chi}_c2$ decays with over 4σ significance.

Abstract

Using $(27.12\pm 0.14)\times10^{8}$ $\psi(3686)$ events collected with the BESIII detector, the decay $\chi_{c0}\to\Sigma^{+}\bar{\Sigma}^{-}\eta$ is observed for the first time with a statistical significance of $7.0\sigma$, and evidence for $\chi_{c1}\to\Sigma^{+}\bar{\Sigma}^{-}\eta$ and $\chi_{c2}\to\Sigma^{+}\bar{\Sigma}^{-}\eta$ is found with statistical significances of $4.3\sigma$ and $4.6\sigma$, respectively. The branching fractions are determined to be $\mathcal{B}(\chi_{c0}\to\Sigma^{+}\bar{\Sigma}^{-}\eta)=({1.26 \pm 0.20 \pm 0.13}) \times 10^{-4}, ~\mathcal{B}(\chi_{c1}\to\Sigma^{+}\bar{\Sigma}^{-}\eta)=({5.10 \pm 1.21 \pm 0.67}) \times 10^{-5}$, and $\mathcal{B}(\chi_{c2}\to\Sigma^{+}\bar{\Sigma}^{-}\eta)=({5.46 \pm 1.18 \pm 0.50}) \times 10^{-5}$, where the first uncertainties are statistical, and the second ones are systematic.