Measurement of the branching fraction of D + → τ + ν τ

Journal article

By analyzing e+e− collision data with an integrated luminosity of 7.9 fb−1 collected with the BESIII detector at the center-of-mass energy of 3.773 GeV, the branching fraction of D+→ τ+ντ is determined as B = (9.9 ± 1.1stat± 0.5syst) × 10−4. Using the most precise result B(D+→ μ+νμ) = (3.981 ± 0.079stat± 0.040syst) × 10−4 [1], we determine Rτ/μ = Γ(D+ → τ+ντ)/Γ(D+ → μ+νμ) = 2.49 ± 0.31, achieving a factor of two improvement in precision compared to the previous BESIII result. This measurement is in agreement with the standard model prediction of lepton flavor universality within one standard deviation.

Authors: Ablikim, M; Achasov, MN; Adlarson, P; Afedulidis, O; Ai, XC

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2025
• Issue: 1
• Article number: 89
• Publication date: 2025-01-17
• Acceptance date: 2024-12-21
• DOI: 10.1007/jhep01(2025)089
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Flavour Physics; e+-e− Experiments; Branching fraction; Charm Physics