2024/01/10 by The BESIII Collaboration
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2401.05457
openalex publication_date 2024/01/10 · openalex created_date 2024/01/13 · openalex updated_date 2026/07/28
Based on (27.12± 0.14)× 108 ψ(2S) events collected with the BESIII detector, we search for the decay ηc (2S) → π+ π- ηc with ηc→ KS0 K±π∓ and ηc→ K+K-π0. No significant signal is observed, and the upper limit on the product branching fraction B(ψ(2S)→ γηc(2S))\timesB(ηc (2S) → π+ π- ηc) is determined to be 2.21×10-5 at the 90% confidence level. In addition, the analysis of the process ψ(2S)→γηc(2S), ηc(2S)→ π+π-K0SK±π∓ gives a clear ηc(2S) signal with a statistical significance of 10σ for the first time, %The product branching fraction B(ψ(2S)→ γηc(2S))\timesB(ηc(2S)→ π+π-K0SKπ) is measured to be (9.31 ± 0.72 ± 2.77)× 10-6, and and the branching fraction B(ηc(2S)→ π+π-K0SK±π∓) is determined to be (1.33 ± 0.11 ± 0.4 ± 0.95 )× 10-2, where the first uncertainty is statistical, the second is systematic, and the third uncertainty is due to the quoted B(ψ(2S)→ γηc(2S)).