摘要
The decay ψ（2S）→Ω-Ω＋ is analyzed using 14×106 ψ（2S） events recorded by the Beijing Spectrometer Ⅱ （BESⅡ） at the Beijing Electron Positron Collider （BEPC）. Based upon events with no missing charged tracks and a satisfactory four-constraint kinematic t, we determine the upper limit for the branching fraction of ψ（2S）→Ω-Ω＋ to be 1.5×104 at a 90% confidence level. By including events with one missing charged track, we are able to report the first evidence of an Ω＋ signal with a statistical signi cance of 3.1｜σ. The branching fraction of ψ（2S）Ω＋ is determined to be （4.80±1.56（stat）±1.30（sys））105.
The decay ψ（2S）→Ω-Ω＋ is analyzed using 14×106 ψ（2S） events recorded by the Beijing Spectrometer Ⅱ （BESⅡ） at the Beijing Electron Positron Collider （BEPC）. Based upon events with no missing charged tracks and a satisfactory four-constraint kinematic t, we determine the upper limit for the branching fraction of ψ（2S）→Ω-Ω＋ to be 1.5×104 at a 90% confidence level. By including events with one missing charged track, we are able to report the first evidence of an Ω＋ signal with a statistical signi cance of 3.1｜σ. The branching fraction of ψ（2S）Ω＋ is determined to be （4.80±1.56（stat）±1.30（sys））105.
基金
Supported by National Natural Science Foundation of China （10491300, 10225524, 10225525, 10425523, 10625524, 10521003, 10821063, 10825524）, Chinese Academy of Sciences （KJ 95T-03）, 100 Talents Program of CAS （U-11, U-24, U-25）, Knowledge Innovation Project of CAS （U-602, U-34 （IHEP））, National Natural Science Foundation of China （10775077, 10225522） （Tsinghua University）, and Department of Energy （DE-FG02-04ER41291） （U. Hawaii）
