Çetin, Serkant Ali2020-06-202020-06-202018-08-101873-24450370-2693https://hdl.handle.net/11411/2256https://doi.org/10.1016/j.physletb.2018.05.038Using a data sample of 448.1 x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, we report the first observation of the electromagnetic Dalitz decay psi(3686) -> eta'e(+)e(-), with significances of 7.0 sigma and 6.3 sigma when reconstructing the eta' meson via its decay modes eta' -> gamma pi(+)pi(-) and eta' -> pi(+)pi(-) eta (eta -> gamma gamma), respectively. The weighted average branching fraction is determined to be B(psi(3686) -> eta'e(+)e(-)) = (1.90 +/- 0.25 +/- 0.11) x 10(-6), where the first uncertainty is statistical and the second systematic. (C) 2018 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).eninfo:eu-repo/semantics/openAccesse(+)e(-) AnnihilationDalitz decayCharmoniumBESIIIArticle2-s2.0-8505008612010.1016/j.physletb.2018.05.038Q2WOS:000441762300062