Observation of the Charmonium Decay ηc→γγ in J/ψ→γηc

The BESIII collaboration

doi:10.1103/PhysRevLett.134.181901

Observation of the Charmonium Decay ηc→γγ in J/ψ→γηc

The BESIII collaboration

Institute of Higher Research

CAS - Institute of High Energy Physics
Budker Institute of Nuclear Physics of the Siberian Branch of the RAS
Novosibirsk State University
Uppsala University
Zhengzhou University
Chinese Academy of Sciences
Johannes Gutenberg University Mainz
University of Turin
National Institute for Nuclear Physics
University of Science and Technology of China
Southeast University, Nanjing
Joint Institute for Nuclear Research
Peking University
University of Chinese Academy of Sciences
National Centre for Nuclear Research
Mongolian Academy of Sciences
Carnegie Mellon University
University of Münster
Wuhan University
Lanzhou University
Istinye University
Nankai University
Moscow Institute of Physics and Technology
China University of Geosciences, Wuhan
Soochow University
Henan University
Nanjing University
North China Electric Power University
Tsinghua University
CAS - Institute of Modern Physics
Jilin University
Hunan University
Chung-Ang University
Fudan University
Shandong University
Yunnan University
Helmholtz Institute Mainz
Ruhr University Bochum
University of South China
University of Jinan
Liaoning University
Inner Mongolia University
Henan Normal University
Sun Yat-Sen University
University of Eastern Piedmont
Nanjing Normal University
University of Ferrara
University of Manchester
University of Oxford
GSI Helmholtz Centre for Heavy Ion Research
Guangxi University
Shandong Normal University
Indiana University Bloomington
University of Hawai'i at Mānoa
Suranaree University of Technology
South China Normal University
University of the Punjab
Hangzhou Normal University
Huangshan College
University of Groningen
Indian Institute of Technology Madras
Justus Liebig University Giessen
Qufu Normal University
Liaoning Normal University
Renmin University of China
Hebei University
China Center of Advanced Science and Technology World Laboratory
Sichuan University
Guangxi Normal University
Shanxi University
Central China Normal University
Henan University of Science and Technology
Henan University of Technology
Central South University
Zhejiang University
Goethe University Frankfurt
COMSATS University Islamabad
IBA
University of Perugia
Universidad de Tarapacá
Russian Research Centre Kurchatov Institute
Hunan Normal University
Swiss Federal Institute of Technology Lausanne
Shanghai Jiao Tong University
Ministry of Education of the People's Republic of China
Near East University
Yantai University
Beihang University
University of Bristol
Shanxi Normal University
University of Science and Technology Liaoning

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

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.

Original language	English
Article number	181901
Journal	Physical Review Letters
Volume	134
Issue number	18
DOIs	https://doi.org/10.1103/PhysRevLett.134.181901
State	Published - 9 May 2025

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10.1103/PhysRevLett.134.181901

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@article{39624a5e54c54b058c3ccab2dabc3ac9,

title = "Observation of the Charmonium Decay ηc→γγ in J/ψ→γηc",

abstract = "Using (2712.4±14.3){\texttimes}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){\texttimes}B(ηc→γγ)=(5.23±0.26stat±0.30syst){\texttimes}10-6. This result is consistent with the lattice QCD calculation (5.34±0.16){\texttimes}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.",

author = "M. Ablikim and Achasov, \{M. N.\} and P. Adlarson and Ai, \{X. C.\} and S. Kabana and \{The BESIII collaboration\}",

note = "Publisher Copyright: {\textcopyright} 2025 authors. Published by the American Physical Society.",

year = "2025",

month = may,

day = "9",

doi = "10.1103/PhysRevLett.134.181901",

language = "English",

volume = "134",

journal = "Physical Review Letters",

issn = "0031-9007",

number = "18",

}

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

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 -

Observation of the Charmonium Decay ηc→γγ in J/ψ→γηc

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