Measurement of branching fractions of J/ψ and ψ(3686) decays to Σ+ and $\overline{\Sigma }$ −

Using 1310.6 × 106 J/ψ and 448.1 × 106 ψ(3686) events collected with the BESIII detector, the branching fractions of J/ψ decays to Σ+ $\overline{\Sigma }$ − is measured to be (10.61 ± 0.04 ± 0.36) × 10 −4, which is significantly more precise than the current world average. The branching fractions of ψ(3686) decays to Σ+ $\overline{\Sigma }$ − is measured to be (2.52 ± 0.04 ± 0.09) × 10 −4, which is consistent with the previous measurements. In addition, the ratio of $B$ (ψ(3686) → Σ+ $\overline{\Sigma }$ − )/ $B$ (J/ψ → Σ+ $\overline{\Sigma }$ − ) is determined to be (23.8 ± 1.1)% which violates the "12% rule".