Search for the Weak Decay η′ → k^± π^∓ and Precise Measurement of the Branching Fraction ℬ(J/ψ → φη′)


We present the first search for the rare decay of η′ into K^± π^∓ in J/ψ → φη′, using a sample of 1.3 ×10⁹ J/ψ events collected with the BESIII detector. No significant signal is observed, and the upper limit at the 90% confidence level for the ratio ℬ(η′ → K^± π^∓) / ℬ(η′ → γπ⁺π⁻) is determined to be 1.3 × 10⁻⁴. In addition, we report the measurement of the branching fraction of J/ψ → φη′ to be [5.10 ± 0.03(stat) ± 0.32(syst)] × 10⁻⁴, which agrees with previous results from BESII.



Hadrons—Decay, Electron-positron interactions, J/ψ (J/psi) meson, Branching ratios (Nuclear physics), Particles (Nuclear physics)—Charm, Weak interactions (Nuclear physics)


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