Observation of ? (3686) ?3?

Using (2.712±0.014)×109 ?(3686) events collected by the BESIII detector operating at the BEPCII collider, we report the first observation of ?(3686)?3? decay with a significance larger than 10?. The branching fraction of this decay is determined to be (1.46±0.05±0.17)×10-5, where the first uncertainty is statistical and the second is systematic. No significant structure is observed in the ?? invariant mass spectra. © 2024 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.