TY - JOUR

T1 - Improved measurement of the branching fraction of hc → γη′/η and search for hc → γπ0

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 - Nikolaev, I. b.

AU - Мучной, Николай Юрьевич

PY - 2024/8/22

Y1 - 2024/8/22

N2 - The processes hc→ γP (P = η′, η, π0) are studied with a sample of (27.12 ± 0.14) × 108ψ(3686) events collected by the BESIII detector at the BEPCII collider. The decay hc→ γη is observed for the first time with the significance of 9.0 σ, and the branching fraction is determined to be (3.77 ± 0.55 ± 0.13 ± 0.26) × 10−4, while B (hc→ γη′) is measured to be (1.40 ± 0.11 ± 0.04 ± 0.10) × 10−3, where the first uncertainties are statistical, the second systematic, and the third from the branching fraction of ψ(3686) → π0hc. The combination of these results allows for a precise determination of Rhc=Bhc→γηBhc→γη′, which is calculated to be (27.0 ± 4.4 ± 1.0)%. The results are valuable for gaining a deeper understanding of η − η′ mixing, and its manifestation within quantum chromodynamics. No significant signal is found for the decay hc → γπ0, and an upper limit is placed on its branching fraction of B(hc → γπ0) < 5.0 × 10−5, at the 90% confidence level.

AB - The processes hc→ γP (P = η′, η, π0) are studied with a sample of (27.12 ± 0.14) × 108ψ(3686) events collected by the BESIII detector at the BEPCII collider. The decay hc→ γη is observed for the first time with the significance of 9.0 σ, and the branching fraction is determined to be (3.77 ± 0.55 ± 0.13 ± 0.26) × 10−4, while B (hc→ γη′) is measured to be (1.40 ± 0.11 ± 0.04 ± 0.10) × 10−3, where the first uncertainties are statistical, the second systematic, and the third from the branching fraction of ψ(3686) → π0hc. The combination of these results allows for a precise determination of Rhc=Bhc→γηBhc→γη′, which is calculated to be (27.0 ± 4.4 ± 1.0)%. The results are valuable for gaining a deeper understanding of η − η′ mixing, and its manifestation within quantum chromodynamics. No significant signal is found for the decay hc → γπ0, and an upper limit is placed on its branching fraction of B(hc → γπ0) < 5.0 × 10−5, at the 90% confidence level.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85202939402&origin=inward&txGid=02af8621f90f2e1aa8b2aa88a3cc1c41

U2 - 10.1007/JHEP08(2024)180

DO - 10.1007/JHEP08(2024)180

M3 - Article

VL - 2024

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1029-8479

IS - 8

M1 - 180

ER -