Abstract:
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A detailed analysis of ψ(2S) → Ω− Ω+ ( Ω− → ΛK − , Λ → pπ − , Ω+ → ΛK + and
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Λ → pπ + ) decay channel has been undertaken in this work. About 14 million ψ(2S)
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decays recorded by Beijing Spectrometer II (BESII) at Beijing Electron Positron
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Collider (BEPC), have been used. In earlier measurements of ψ(2S) → Ω− Ω+ , no
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significant signal of Ω− or Ω+ was found. Through a new technique of selecting
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events with one missing charge track also, we report a first evidence of Ω− and Ω+
signals with statistical significance levels of 5.3 σ and 4.6 σ, respectively. A branching
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fraction of ψ(2S) → Ω− Ω+ has been determined to be (3.21 ± 1.25 ± 0.97) × 10−5 .
The errors are statistical and systematic, respectively.
