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利用北京正负电子对撞机 (BEPC)上的北京谱仪 (BES)收集的 7 8× 1 0 6 个J ψ事例 ,研究了J ψ→Σ0 Σ0 衰变 .其衰变分支比为BR(J ψ→Σ0 Σ0 ) =( 0 97±0 0 4± 0 2 4 )× 1 0 - 3,角分布具有 dNdcosθ=N0 ( 1 +αcos2 θ)的形式 ,α值等于 -0 2 1± 0 2 7± 0 1 3 .
The decay of J ψ → Σ0 Σ0 is studied by using 7 8 × 1 0 6 J ψ cases collected by Beijing spectrometer (BES) at BEPC. The decay branching ratio is BR (J ψ → Σ0 Σ0) = (0 97 ± 0 0 4 ± 0 2 4) × 1 0 - 3, the angular distribution has the form dNdcosθ = N0 (1 + αcos2 θ) with α equal to -0 2 1 ± 0 2 7 ± 0 1 3.