Abstract
We report the first measurement of the Michel parameter in the decay with a new method proposed just recently. The measurement is based on the reconstruction of the events with subsequent muon decay in flight in the Belle central drift chamber. The analyzed data sample of collected by the Belle detector corresponds to approximately pairs. We measure , which is in agreement with the standard model prediction of . Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.
- Received 21 March 2023
- Accepted 6 June 2023
DOI:https://doi.org/10.1103/PhysRevLett.131.021801
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