The two-photon radiative decay process J/ψ→2γ+hadrons was studied,and the main contribution processes,J/ψ→2γ+ggg and J/ψ→2γ+qˉq,were calculated.With the specific conditions at the BESIII,this rare decay process and the main background process e+e?→γγ+hadrons(qˉq)were investigated.The results show that the ratio of signal to background can reach 1.24 with optimized selection criteria at the BESIII.In addition,distributions of the signal and background are presented.All the results show that the signal is large enough to be experimentally measured.
BESⅢ data show a particular angular distribution for the decay of J/Ψ and Ψ(2S) mesons into ■ and Σ~0Σ~0 hyperons: the angular distribution of the decay Ψ(2S) →Σ~0Σ~0 exhibits an opposite trend with respect to the other three channels: J/Ψ→■, J/Ψ→Σ~0Σ~0 and Ψ(2S) →■. We define a model to explain the origin of this phenomenon.
