Abstract
We search for lepton-flavor-violating and decays, where is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of , produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known and decays. We report 95% confidence-level upper limits on the branching-fraction ratio in the range and on in the range for masses between 0 and . These results provide the most stringent bounds on invisible boson production from decays.
- Received 7 December 2022
- Accepted 23 February 2023
DOI:https://doi.org/10.1103/PhysRevLett.130.181803
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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