Based on a sample of (1310.6±7.0)×106J/ψ events collected with the BESIII detector, we present measurements of J/ψ and η′ absolute branching fractions using the process J/ψ→γη′. By analyzing events where the radiative photon converts into an e+e-pair, the branching fraction for J/ψ→γη′ is measured to be (5.27±0.03±0.05)×10-3. The absolute branching fractions of the five dominant decay channels of the η′ are then measured for the first time and are determined to be B(η′→γπ+π-)=(29.90±0.03±0.55)%, B(η′→ηπ+π-)=(41.24±0.08±1.24)%, B(η′→ηπ0π0)=(21.36±0.10±0.92)%, B(η′→γω)=(2.489±0.018±0.074)%, and B(η′→γγ)=(2.331±0.012±0.035)%, where the first uncertainties are statistical and the second systematic.
Bibliographical noteFunding 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 Basic Research Program of China under Contract No. 2015CB856700; National Natural Science Foundation of China (NSFC) under Contracts No. 11335008, No. 11425524, No. 11625523, No. 11635010, No. 11675184, No. 11735014; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. U1532257, No. U1532258, No. U1732263; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003, No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; Shandong Natural Science Funds for Distinguished Young Scholar under Contract No. JQ201402; German Research Foundation DFG under Contracts No. Collaborative Research Center CRC 1044, No. FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy; Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) under Contract No. 530-4CDP03; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; The Swedish Research Council; U.S. Department of Energy under Contracts No. DE-FG02-05ER41374, No. DE-SC-0010118, No. DE-SC-0010504, No. DE-SC-0012069; University of Groningen (RuG) and the Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), Darmstadt.
© 2019 authors. Published by the American Physical Society.