J/ψ→γγV(ρ,φ)衰变的实验研究

Study of Decay J/ψ→γγV(ρ,φ)

利用北京谱仪 (BES)收集的 7 8× 1 0 6 J/ ψ事例 ,对J/ ψ→γγV(ρ,)衰变道中的η(1 43 0 )共振态进行了分析 .从J/ ψ→γγρ衰变模式得到其质量及衰变宽度分别为 1 43 1± 1 7MeV和 88± 2 8MeV ,衰变分支比Br(J/ ψ→γη(1 43 0 ) )Br(η(1 43 0 )→γρ) =(1 1± 0 5± 0 3 )× 1 0 - 4;而从J/ ψ→γγ衰变模式得到其质量及衰变宽度分别为 1 42 4± 1 5MeV和 73± 58MeV ,衰变分支比Br(J/ ψ→γη(1 43 0 ) )Br(η(1 43 0 )→γ) =(2 0± 1 0± 0 6)× 1 0 - 4.

Based on 7.8×10 6 J/ψ events collected by BES experiment,J/ψ radiative decay J/ψ→γγV(ρ,) have been studied. The η(1430) resonance has been observed in these two channels respectively. Its mass,width and branching ratio are 1431±17MeV,88±28MeV,and Br (J/ψ→γη(1430)) Br (η(1430)→γρ)=(1.1±0.5±0.3)×10 -4 from J/ψ→γγρ mode,1424±15MeV,73±58MeV,and Br (J/ψ→γη(1430)) Br (η(1430)→γ)=(2.0±1 0±0.6)×10 -4 from J/ψ→γγ mode.