J/ψ和ψ(3686)衰变到Σ0Σ̄0η的分支比的首次测量
First measurements of the branching fractions of $J/ψ$ and $ψ(3686) \to Σ^{0} \barΣ^{0}η$
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中文总结 AI 辅助
BESIII合作组利用BEPCII采集的J/ψ和ψ(3686)事例，首次测量了两者衰变到Σ0Σ̄0η的分支比，结果与12%规则相符且无显著中间态或阈值增强。
中文摘要 AI 辅助
基于在北京正负电子对撞机BEPCII上使用北京谱仪BESIII采集的(10087±44)×10⁶个J/ψ事例和(2712±14)×10⁶个ψ(3686)事例，首次观测到强子衰变过程J/ψ→Σ0Σ̄0η和ψ(3686)→Σ0Σ̄0η。测量得到对应的分支比分别为ℬ(J/ψ→Σ0Σ̄0η)=(7.5±0.3±0.8)×10⁻⁵和ℬ(ψ(3686)→Σ0Σ̄0η)=(1.3±0.1±0.1)×10⁻⁵，其中第一个不确定度为统计不确定度，第二个为系统不确定度。确定比值Q≈[ℬ(ψ(3686)→Σ0Σ̄0η)]/[ℬ(J/ψ→Σ0Σ̄0η)]为(17.3±1.5±1.7)%，在3.0σ范围内与12%规则相符。在Σ0(Σ̄0)η和Σ0Σ̄0的不变质量谱中未观测到显著的中间态或阈值增强。
英文摘要
Based on $(10087 \pm 44) \times 10^6$ $J/ψ$ and $(2712 \pm 14) \times 10^6$ $ψ(3686)$ events collected with the BESIII detector at the BEPCII collider, the hadronic decays $J/ψ\to Σ^{0} \barΣ^{0} η$ and $ψ(3686) \to Σ^{0} \barΣ^{0} η$ are observed for the first time. The corresponding branching fractions are measured to be $\mathcal{B}(J/ψ\to Σ^{0} \barΣ^{0}η)= (7.5 \pm 0.3 \pm 0.8) \times 10^{-5}$ and $\mathcal{B}(ψ(3686) \to Σ^{0} \barΣ^{0}η)= (1.3\pm 0.1 \pm 0.1) \times 10^{-5}$, respectively, where the first uncertainties are statistical, and the second systematic. The ratio $\text{Q} \approx \frac{\mathcal{B}(ψ(3686) \to Σ^{0} \barΣ^{0} η)}{\mathcal{B}(J/ψ\to Σ^{0} \barΣ^{0} η)}$ is determined to be $(17.3 \pm 1.5 \pm 1.7)\%$, which is con sistent with the 12\%-rule within 3.0$σ$.~No significant intermediate states or threshold enhancements are observed in the $Σ^0$($\barΣ^{0}$)$η$ and $Σ^0$$\barΣ^{0}$ invariant mass spectra.
