Observation of the Leptonic Decay D+ →τ+ντ


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Ablikim M., Achasov M., Adlarson P., Ahmed S., Albrecht M., Alekseev M., ...More

Physical Review Letters, vol.123, no.21, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 123 Issue: 21
  • Publication Date: 2019
  • Doi Number: 10.1103/physrevlett.123.211802
  • Journal Name: Physical Review Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Ankara University Affiliated: Yes

Abstract

© 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" 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.We report the first observation of D+→τ+ντ with a significance of 5.1σ. We measure B(D+→τ+ντ)=(1.20±0.24stat±0.12syst)×10-3. Taking the world average B(D+→μ+νμ)=(3.74±0.17)×10-4, we obtain Rτ/μ=Γ(D+→τ+ντ)/Γ(D+→μ+νμ)=3.21±0.64stat±0.43syst., which is consistent with the standard model expectation of lepton flavor universality. Using external inputs, our results give values for the D+ decay constant fD+ and the Cabibbo-Kobayashi-Maskawa matrix element |Vcd| that are consistent with, but less precise than, other determinations.