Ablikim, M.Achasov M.N.Adlarson P.Çetin, Serkant AliKolcu, Onur Buğra2025-04-182025-04-182024Ablikim, M., Achasov, M. N., Adlarson, P., Afedulidis, O., Ai, X. C., Aliberti, R., ... & Huang, G. S. (2024). Search for η c (2 S)→ π+ π-η c and η c (2 S)→ π+ π-KS 0 K±π∓ decays. Physical Review D, 109(7), 072017.24700010http://dx.doi.org/10.1103/PhysRevD.109.072017https://hdl.handle.net/20.500.12713/6876Based on (27.12 +/- 0.14) x 10(8) psi(2S) events collected by the BESIII detector, we search for the decay eta(c)(2S) -> pi(+)pi(-)eta(c) via psi(2S) -> gamma eta(c)(2S). No significant signal is observed, and the upper limit on the product branching fraction B(psi(2S) -> gamma eta(c) (2S)) x B(eta(c) (2S) -> pi(+)pi(-)eta(c)) is determined to be 2.21 x 10(-5) at the 90% confidence level. In addition, the eta(c)(2S) -> pi(+)pi(-KSK +/-)-K-0 pi(-/+) decay is studied via psi(2S) -> gamma eta(c)(2S) and is observed with a statistical significance of 10 sigma for the first time. The branching fraction of eta(c)(2S) -> pi(+)pi(-KSK +/-)-K-0 pi(-/+) is determined to be (1.33 +/- 0.11 +/- 0.40 +/- 0.95)x10(-2), where the first uncertainty is statistical, the second is systematic, and the third uncertainty is due to the quoted B(psi(2S) -> gamma eta(c)(2S)).eninfo:eu-repo/semantics/openAccessArticle1097113WOS:0012700509000012-s2.0-85192753739Q110.1103/PhysRevD.109.072017Q1