@article{c71ccdd7b96142e5aee2f694676554cc,
title = "Observation of ψ (3770) →ηJ/ψ",
abstract = "Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, the Born cross section of the process e+e-→ηJ/ψ at a center-of-mass energy s=3.773 GeV is measured to be (8.88±0.87±0.42) pb. We fit the cross section line shape before correcting for the initial state radiation from s=3.773 to 4.600 GeV to obtain the branching fraction B(ψ(3770)→ηJ/ψ). We obtain B(ψ(3770)→ηJ/ψ)=(11.3±5.9±1.1)×10-4 when the ψ(3770) decay amplitude is added coherently to the other contributions, and (8.7±1.0±0.8)×10-4 when it is added incoherently. Here the quoted uncertainties are statistical and systematic, respectively. In both cases, the statistical significance of ψ(3770) resonance is above 7σ. This is the first time the decay ψ(3770)→ηJ/ψ is observed with a statistical significance greater than 5σ.",
author = "{BESIII Collaboration} and M. Ablikim and Achasov, {M. N.} and N. Kalantar-Nayestanaki and R. Kappert and M. Kavatsyuk and J. Messchendorp and V. Rodin",
note = "Funding Information: The BESIII collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key Research and Development Program of China under Contracts No. 2020YFA0406300, No. 2020YFA0406400; National Natural Science Foundation of China (NSFC) under Contracts No. 11625523, No. 11635010, No. 11735014, No. 11822506, No. 11835012, No. 11935015, No. 11935016, No. 11935018, No. 11961141012, No. 12022510, No. 12025502, No. 12035009, No. 12035013, No. 12061131003; The key scientific research Projects of colleges and universities in Henan Province (21A140012); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. U1732263, No. U1832207, No. U2032108; CAS Key Research Program of Frontier Sciences under Contract No. QYZDJ-SSW-SLH040; the CAS Center for Excellence in Particle Physics (CCEPP); 100 Talents Program of CAS; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; European Union Horizon 2020 research and innovation programme under Contract No. Marie Sklodowska-Curie grant agreement No. 894790; German Research Foundation DFG under Contracts No. 443159800, Collaborative Research Center CRC 1044, FOR 2359, GRK 2149; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; Olle Engkvist Foundation under Contract No. 200-0605; STFC (United Kingdom); The Knut and Alice Wallenberg Foundation (Sweden) under Contract No. 2016.0157; The Royal Society, UK under Contracts No. DH140054, No. DH160214; The Swedish Research Council; U.S. Department of Energy under Contracts No. DE-FG02-05ER41374, No. DE-SC-0012069. Publisher Copyright: {\textcopyright} 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the {"}https://creativecommons.org/licenses/by/4.0/{"}Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.",
year = "2023",
month = may,
day = "15",
doi = "10.1103/PhysRevD.107.L091101",
language = "English",
volume = "107",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "AMER PHYSICAL SOC",
number = "9",
}