We report on a comparison of two possible Λc+ spin hypotheses, J=12 and 32, via the process e+e-→Λc+Λ¯c-, using the angular distributions of Λc+ decays into pKS0, Λπ+, ς0π+, and ς+π0. The data were recorded at s=4.6 GeV with the BESIII detector and correspond to an integrated luminosity of 587 pb-1. The Λc+ spin is determined to be J=12, with this value favored over the 32 hypothesis with a significance corresponding to more than 6 Gaussian standard deviations.
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 Contracts No. 2015CB856700, No. 2020YFA0406300, No. 2020YFA0406400; National Natural Science Foundation of China (NSFC) under Contracts No. 11875262, No. 11835012, No. 11625523, No. 11635010, No. 11735014, No. 11822506, No. 11835012, No. 11935015, No. 11935016, No. 11935018, No. 11961141012; 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. U2032110, No. U1732263, No. U1832207, No. U1832107; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003, No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; Fundamental Research Funds for the Central Universities; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; German Research Foundation DFG under Contracts Nos. Collaborative Research Center CRC 1044, FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; 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; Olle Engkvist Foundation under Contract No. 200-0605.
© 2021 authors. Published by the American Physical Society.