Current studentsExisting staffContact us
 

Test of lepton flavor universality with measurements of 𝑅⁡(𝐷⁺) and 𝑅⁡(𝐷*⁺) using semileptonic 𝐵 tagging at the Belle II experiment

Files

hdl_150314.pdf (2.51 MB)
  (Published version)

Date

2025

Authors

Adachi, I.
Adamczyk, K.
Aggarwal, L.
Ahmed, H.
Aihara, H.
Akopov, N.
Alghamdi, S.
Alhakami, M.
Aloisio, A.
Althubiti, N.

Editors

Advisors

Journal Title

Journal ISSN

Volume Title

Type:

Journal article

Citation

Physical Review D, 2025; 112(3):032010-1-032010-23

Statement of Responsibility

Belle II Collaboration

Conference Name

DOI

10.1103/fmn3-h8fy

Abstract

We report measurements of the ratios of branching fractions ℛ⁡(𝐷(*)+)=ℬ⁡( ¯ 𝐵 0→𝐷(*)+⁢𝜏−⁢ ¯ 𝜈 𝜏)/ℬ⁡( ¯ 𝐵 0→𝐷(*)+⁢ℓ−⁢ ¯ 𝜈 ℓ) , where ℓ denotes either an electron or a muon. These ratios test the universality of the charged-current weak interaction. The results are based on a 365  fb−1 data sample collected with the Belle II detector at the SuperKEKB 𝑒+⁢𝑒− collider, which operates at a center-of-mass energy corresponding to the ϒ⁡(4⁢𝑆) resonance, just above the threshold for 𝐵⁢ ¯ 𝐵 production. Signal candidates are reconstructed by selecting events in which the companion 𝐵 meson from the ϒ⁡(4⁢𝑆) →𝐵⁢ ¯ 𝐵 decay is identified in semileptonic modes. The 𝜏 lepton is reconstructed via its leptonic decays. We obtain ℛ⁡(𝐷+)=0.418+0.075 −0.073⁢(stat)+0.049 −0.056⁢(syst) and ℛ⁡(𝐷*+)=0.306+0.035 −0.033⁢(stat)+0.016 −0.018⁢(syst) , which are consistent with world average values. Accounting for the correlation between them, these values differ from the Standard Model expectation by a collective significance of 1.7 standard deviations.

School/Discipline

Dissertation Note

Provenance

Description

Published 26 August 2025

Access Status

Rights

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.

License

Grant ID

http://purl.org/au-research/grants/arc/DP200101792
 http://purl.org/au-research/grants/arc/DP210101900
 http://purl.org/au-research/grants/arc/DP210102831
 http://purl.org/au-research/grants/arc/DE220100462
 http://purl.org/au-research/grants/arc/LE210100098
 http://purl.org/au-research/grants/arc/LE230100085

Published Version

https://doi.org/10.1103/fmn3-h8fy

Call number

Persistent link to this record

https://hdl.handle.net/2440/150314