Abstract
We present a study of the lineshape in the decay using a data sample of pairs collected at the resonance with the Belle detector at the KEKB asymmetric-energy collider. The peak near the threshold in the invariant mass spectrum is fitted using a relativistic Breit-Wigner lineshape. We determine the mass and width parameters to be and , respectively. The branching fraction is found to be . The signal from decays is observed for the first time with significance, and the ratio of branching fractions between charged and neutral decays is measured to be . The peak is also studied using a Flatté lineshape. We determine the lower limit on the coupling constant to be 0.075 at 95% credibility in the parameter region where the ratio of to the mass difference from the threshold is equal to , as measured by LHCb.
- Received 3 February 2023
- Accepted 15 May 2023
DOI:https://doi.org/10.1103/PhysRevD.107.112011
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Published by the American Physical Society under the terms of the 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.
Published by the American Physical Society