The baryonic decay Ds+→pn̄ is observed, and the corresponding branching fraction is measured to be (1.21±0.10±0.05)×10-3, where the first uncertainty is statistical and second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII e+e- double-ring collider with a center-of-mass energy of 4.178 GeV and an integrated luminosity of 3.19 fb-1. The result confirms the previous measurement by the CLEO Collaboration and is of greatly improved precision. This result will improve our understanding of the dynamical enhancement of the W-annihilation topology in the charmed meson decays.
Bibliographical noteFunding Information:
The BESIII Collaboration thanks the staff of BEPCII, the IHEP computing center and the supercomputing center of USTC for their strong support. The authors are grateful to Professor Hai-Yang Cheng, Dr. Xian-Wei Kang and Dr. Fu-Sheng Yu for enlightening discussions. This work is supported in part by National Key Basic Research Program of China under Contracts No. 2015CB856700; National Natural Science Foundation of China (NSFC) under Contracts No. 11405046, No. 11605198, No. 11235011, No. 11335008, No. 11425524, No. 11625523, No. 11635010, No. 11375170, No. 11275189, No. 11475164, No. 11475169, No. 11605196, No. 11705192; 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. U1332201, No. U1532102, No. U1532257, No. U1532258, No. U1732263, No. U1832103; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003 and No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; National 1000 Talents Program of China; Institute of Nuclear, Particle, Astronomy and Cosmology (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; 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. 5304CDP03; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Natural Science Foundation of China (NSFC) under Contracts No. 11505034 and No. 11575077; 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; WCU Program of National Research Foundation of Korea under Contract No. R32-2008-000-10155-0.
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