Measurement of the branching fraction of Ds∗+→e+e−Ds+
Using 7.33 fb⁻¹ of e+e− collision data collected by the BESIII experiment, the paper reports a measurement of the branching fraction for the electromagnetic Dalitz decay Ds∗+→e+e−Ds+ as (7.28±0.61stat±0.31syst)×10−3, achieving a 2.5-fold improvement in precision over previous results and providing crucial constraints for theoretical models and related absolute branching fractions.
BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, R. Aliberti, A. Amoroso, Q. An, Y. Bai, O. Bakina, Y. Ban, H. -R. Bao, X. L. Bao, V. Batozskaya, K. Begzsuren, N. Berger, M. Ber (…)2026-06-10⚛️ hep-ex