Observation of the double Dalitz decay eta' -> e(+)e(-)e(+)e(-)

Abstract

Based on (10087±44)×106 J/ψ events collected with the BESIII detector at BEPCII, the double Dalitz decay η′→e+e-e+e-is observed for the first time via the J/ψ→γη′ decay process. The significance is found to be 5.7σ with systematic uncertainties taken into consideration. Its branching fraction is determined to be B(η′→e+e-e+e-)=(4.5±1.0(stat)±0.5(sys))×10-6. © 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.