Çetin, Serkant Ali2021-04-072021-04-072017-06-021079-71140031-9007https://hdl.handle.net/11411/3497https://doi.org/10.1103/PhysRevLett.118.221802Using 4.479×108???(3686) events collected with the BESIII detector, we search for the decays ?(3686)?e+e??cJ and ?cJ?e+e?J/?, where J=0, 1, 2. The decays ?(3686)?e+e??cJ and ?cJ?e+e?J/? are observed for the first time. The measured branching fractions are B(?(3686)?e+e??cJ)=(11.7±2.5±1.0)×10?4, (8.6±0.3±0.6)×10?4, (6.9±0.5±0.6)×10?4 for J=0, 1, 2, and B(?cJ?e+e?J/?)=(1.51±0.30±0.13)×10?4, (3.73±0.09±0.25)×10?3, (2.48±0.08±0.16)×10?3 for J=0, 1, 2, respectively. The ratios of the branching fractions B(?(3686)?e+e??cJ)/B(?(3686)???cJ) and B(?cJ?e+e?J/?)/B(?cJ??J/?) are also reported. Also, the ? values of helicity angular distributions of the e+e? pair are determined for ?(3686)?e+e??c1,2 and ?c1,2?e+e?J/?.eninfo:eu-repo/semantics/openAccessArticle2-s2.0-8502003456110.1103/PhysRevLett.118.22180228622000Q1WOS:000403603900002