Experiments On BESâ…¢ ψ (2S) â†' (?) (1530) (?) (1530) Measured Accurately

The decays of ψ(2S)â†'Ξ(1530)Ξ(1530) have been studied using the106106ψ(2S)events collected on BESIII experiment. The decays ψ(2S)â†'Ξ0(1530)Ξ0(1530) andψ(2S)â†'Ξ-(1530)Ξ+(1530) are observed for the first time in the world. The branchingfraction ratio of ψ(2S)â†'Ξ0(1530)Ξ0(1530) is measured to be (5.98±0.50(stat.)±0.54(sys.))10-5. The branching fraction ratio of ψ(2S)â†'Ξ-(1530)Ξ+(1530) is measuredto be (3.220.47(stat.))10-5. The measurements provide important experimentalinformation to test the QCD theory. The BESI and CLEO collaborations have investigatedthe decay ψ(2S)â†'Ξ0(1530)Ξ0(1530), but no signal events are observed and the upperlimit8.110-5is determined. In our measurements, the statistical significance of the signalis larger than9σ. The charged decay ψ(2S)â†'Ξ-(1530)Ξ+(1530) is observed for the firsttime in the world and its branching fraction ratio is measured precisely.