TY - JOUR

T1 - Observation of ηc(2S)→K+K−η

AU - BESIII Collaboration

AU - Ablikim, M.

AU - Achasov, M. n.

AU - Adlarson, P.

AU - Afedulidis, O.

AU - Ai, X. c.

AU - Aliberti, R.

AU - Amoroso, A.

AU - An, Q.

AU - Bai, Y.

AU - Bakina, O.

AU - Balossino, I.

AU - Ban, Y.

AU - Bao, H.-R.

AU - Batozskaya, V.

AU - Begzsuren, K.

AU - Berger, N.

AU - Berlowski, M.

AU - Bertani, M.

AU - Bettoni, D.

AU - Bianchi, F.

AU - Bianco, E.

AU - Bortone, A.

AU - Briere, R. a.

AU - Brueggemann, A.

AU - Николаев, Иван Борисович

AU - Мучной, Николай Юрьевич

PY - 2024/11/12

Y1 - 2024/11/12

N2 - By analyzing (27.12±0.14)×108 ψ(3686) events accumulated with the BESIII detector, the decay ηc(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)→γηc(2S) and ηc(2S)→K+K−η is measured to be B(ψ(3686)→γηc(2S))×B(ηc(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 ηc(2S)→K+K−η is determined to be B(ηc(2S)→K+K−η)=(3.42±0.46±0.48±2.44)×10−3, where the third uncertainty is due to the branching fraction ofψ(3686)→γηc(2S). Using a recent BESIII measurement of B(ηc(2S)→K+K−π0), we also determine the ratio between the branching fractions of ηc(2S)→K+K−η and ηc(2S)→K+K−π0 to be1.49±0.22±0.25, which is consistent with the previous result of BABAR at a comparable precision level.

AB - By analyzing (27.12±0.14)×108 ψ(3686) events accumulated with the BESIII detector, the decay ηc(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)→γηc(2S) and ηc(2S)→K+K−η is measured to be B(ψ(3686)→γηc(2S))×B(ηc(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 ηc(2S)→K+K−η is determined to be B(ηc(2S)→K+K−η)=(3.42±0.46±0.48±2.44)×10−3, where the third uncertainty is due to the branching fraction ofψ(3686)→γηc(2S). Using a recent BESIII measurement of B(ηc(2S)→K+K−π0), we also determine the ratio between the branching fractions of ηc(2S)→K+K−η and ηc(2S)→K+K−π0 to be1.49±0.22±0.25, which is consistent with the previous result of BABAR at a comparable precision level.

U2 - 10.1103/PhysRevD.110.092003

DO - 10.1103/PhysRevD.110.092003

M3 - Article

VL - 110

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 9

M1 - 92003

ER -