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.
Categories: hep-ex