Observation of the radiative decay D_s (2317)⁺ → D_s^* γ

2025/10/31 by Belle II Collaboration, Abumusabh, M., Adachi, I. +367
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2510.27174

Abstract

We observe the radiative decay D^*_s0(2317)⁺ → D_s^*+ γ for the first time, with a significance exceeding 10 standard deviations. The signal is found in the continuum e⁺ e^- → cc process with the combined data samples of 980.4~\rm fb^-1 and 427.9~\rm fb^-1 collected by the Belle and Belle~II detectors operating at the KEKB and SuperKEKB asymmetric-energy e⁺e^- colliders, respectively. The branching fraction ratio \cal B(D^*_s0(2317)⁺ → D_s^*+ γ)/\cal B(D^*_s0(2317)⁺ → D_s⁺ π⁰) is measured to be [7.14 ± 0.70(\rm stat.) ± 0.23(\rm syst.)]%. This result provides significant new experimental input for the determination of the quark structure of the D^*_s0(2317)⁺, which remains unknown.

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