Measurement of the absolute branching fractions for purely leptonic Ds+ decays


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Ablikim M., Achasov M., Adlarson P., Ahmed S., Albrecht M., Aliberti R., ...More

Physical Review D, vol.104, no.5, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 104 Issue: 5
  • Publication Date: 2021
  • Doi Number: 10.1103/physrevd.104.052009
  • Journal Name: Physical Review D
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, INSPEC, zbMATH
  • Ankara University Affiliated: No

Abstract

© 2021 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 new measurements of the branching fraction B(Ds+→ℓ+ν), where is either μ+ or τ+(→π+ν¯τ), based on 6.32 fb-1 of electron-positron annihilation data collected by the BESIII experiment at six center-of-mass energy points between 4.178 and 4.226 GeV. Simultaneously floating the Ds+→μ+νμ and Ds+→τ+ντ components yields B(Ds+→τ+ντ)=(5.21±0.25±0.17)×10-2, B(Ds+→μ+νμ)=(5.35±0.13±0.16)×10-3, and the ratio of decay widths R=Γ(Ds+→τ+ντ)Γ(Ds+→μ+νμ)=9.73-0.58+0.61±0.36, where the first uncertainties are statistical and the second systematic. No evidence of CP asymmetry is observed in the decay rates Ds±→μ±νμ and Ds±→τ±ντ: ACP(μ±ν)=(-1.2±2.5±1.0)% and ACP(τ±ν)=(+2.9±4.8±1.0)%. Constraining our measurement to the Standard Model expectation of lepton universality (R=9.75), we find the more precise results B(Ds+→τ+ντ)=(5.22±0.10±0.14)×10-2 and ACP(τ±ντ)=(-0.1±1.9±1.0)%. Combining our results with inputs external to our analysis, we determine the c→s¯ quark mixing matrix element, Ds+ decay constant, and ratio of the decay constants to be |Vcs|=0.973±0.009±0.014, fDs+=249.9±2.4±3.5 MeV, and fDs+/fD+=1.232±0.035, respectively.