Measurements of ψ(2S) decays to octet baryon–antibaryon pairs

With a sample of 14 × 10 6 ψ ( 2 S ) events collected by the BESII detector at the Beijing Electron Positron Collider (BEPC), the decay channels ψ ( 2 S ) → B 8 B ¯ 8 ( p p ¯ , Λ Λ ¯ , Σ 0 Σ ¯ 0 , Ξ − Ξ ¯ + ) are measured, and their branching ratios are determined to be ( 3.36 ± 0.09 ± 0.25 ) × 10 −4 , ( 3.39 ± 0.20 ± 0.32 ) × 10 −4 , ( 2.35 ± 0.36 ± 0.32 ) × 10 −4 , ( 3.03 ± 0.40 ± 0.32 ) × 10 −4 , respectively. In the decay ψ ( 2 S ) → p p ¯ , the angular distribution parameter α is determined to be 0.85 ± 0.24 ± 0.04 .