Improved Measurements of D⁺ → ηe⁺ν_e and D⁺ → ημ⁺ν_μ

2025/06/03 by BESIII Collaboration, M. N. Achasov, Ablikim, M. +772
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.2506.02521

openalex publication_date 2025/06/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

Using 20.3 fb^-1 of e⁺e^- collision data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector, we measure the branching fractions of D⁺→ ηe⁺ν_e and D⁺→ ημ⁺ν_μ to be (9.75±0.29±0.28)×10^-4 and (9.08±0.35±0.23)×10^-4, where the first and second uncertainties are statistical and systematic, respectively. From a simultaneous fit to their partial decay rates, we determine the product of the hadronic form factor f^η₊(0) and the modulus of the c→ d Cabibbo-Kobayashi-Maskawa matrix element |V_cd| to be f^η₊(0)|V_cd|=0.078±0.002±0.001. Taking the |V_cd| value from the Standard Model global fit as input, we obtain f^η₊(0)=0.345±0.008±0.003. The ratio between the measured branching fractions of D⁺→η⁺μ⁺ν_μ and D⁺→ηe⁺ν_e, is determined to be 0.93±0.05_{\rm stat.}±0.02_{\rm syst.}, indicating no violation of lepton flavor universality.

Related

• Precision Measurement of the Branching Fraction of D⁺→ μ⁺ν_μ
• Study of the decays D⁺→η^(′) e⁺ν_e
• Observation of the decay D⁺_s→ ωπ⁺η
• Precision measurements of semleptonic decays D⁰ → π^-ℓ⁺ν_ℓ and D⁺ → π⁰ℓ⁺ν_ℓ (ℓ =e,μ)
• Measurements of the absolute branching fractions of the doubly Cabibbo-suppressed decays D⁺→ K⁺π⁰, D⁺→ K⁺η and D⁺→ K⁺η^′