Observation of η_c(2S) → K⁺K^-η

2024/08/06 by BESIII Collaboration, Ablikim, M., Achasov, M. N. +645
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2408.02940

Abstract

By analyzing (27.12 ± 0.14)×10⁸ ψ(3686) events accumulated with the BESIII detector, the decay η_c(2S) → K⁺ K^- η is observed for the first time with a significance of 6.2σ after considering systematic uncertainties. The product of the branching fractions of ψ(3686) → γη_c(2S) and η_c(2S) → K⁺ K^- η is measured to be B(ψ(3686) →γη_c(2S))× B(η_c(2S)→ K⁺ K^-η)=(2.39 ± 0.32 ± 0.34) × 10^-6, where the first uncertainty is statistical, and the second one is systematic. The branching fraction of η_c(2S)→ K⁺ K^-η is determined to be B(η_c(2S)→ K⁺ K^-η) = (3.42 ± 0.46 ± 0.48 ± 2.44) × 10^-3, where the third uncertainty is due to the branching fraction of ψ(3686) → γη_c(2S). Using a recent BESIII measurement of B (η_c(2S) → K⁺ K^-π⁰), we also determine the ratio between the branching fractions of η_c(2S) → K⁺ K^-η and η_c(2S) → K⁺ K^-π⁰ to be 1.49 ± 0.22 ± 0.25, which is consistent with the previous result of BaBar at a comparable precision level.

Related

• Search for η_c(2S)→ K⁺ K^- η^′ decay
• Search for η_c (2S)→π⁺π^-η_c and η_c (2S)→π⁺π^-K⁰_S K^±π^∓ decays
• Search for η_c(2S)→ ppK⁺K^- and measurement of χ_cJ→ ppK⁺K^- in ψ(3686) radiative decays
• Search for η_c(2S)→ pp and branching fraction measurements of χ_cJ → pp via ψ(2S) radiative decays
• Observation of χ_c0→Σ⁺Σ^-η and evidence for χ_c1,2→Σ⁺Σ^-η