TY - JOUR
T1 - Observation of the Charmonium Decay ηc→γγ in J/ψ→γηc
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Adlarson, P.
AU - Ai, X. C.
AU - Kabana, S.
AU - The BESIII collaboration
N1 - Publisher Copyright:
© 2025 authors. Published by the American Physical Society.
PY - 2025/5/9
Y1 - 2025/5/9
N2 - Using (2712.4±14.3)×106 ψ(3686) events collected with the BESIII detector at the BEPCII collider, the decay ηc→γγ in J/ψ→γηc is observed. We determine the product branching fraction B(J/ψ→γηc)×B(ηc→γγ)=(5.23±0.26stat±0.30syst)×10-6. This result is consistent with the lattice QCD calculation (5.34±0.16)×10-6 from HPQCD in 2023. By using the world-average values of B(J/ψ→γηc) and the total decay width of ηc, the partial decay width Γ(ηc→γγ) is determined to be (11.30±0.56stat±0.66syst±1.14ref) keV, which deviates from the corresponding world-average value by 3.4σ.
AB - Using (2712.4±14.3)×106 ψ(3686) events collected with the BESIII detector at the BEPCII collider, the decay ηc→γγ in J/ψ→γηc is observed. We determine the product branching fraction B(J/ψ→γηc)×B(ηc→γγ)=(5.23±0.26stat±0.30syst)×10-6. This result is consistent with the lattice QCD calculation (5.34±0.16)×10-6 from HPQCD in 2023. By using the world-average values of B(J/ψ→γηc) and the total decay width of ηc, the partial decay width Γ(ηc→γγ) is determined to be (11.30±0.56stat±0.66syst±1.14ref) keV, which deviates from the corresponding world-average value by 3.4σ.
UR - https://www.scopus.com/pages/publications/105005001462
U2 - 10.1103/PhysRevLett.134.181901
DO - 10.1103/PhysRevLett.134.181901
M3 - Article
C2 - 40408683
AN - SCOPUS:105005001462
SN - 0031-9007
VL - 134
JO - Physical Review Letters
JF - Physical Review Letters
IS - 18
M1 - 181901
ER -