Measurement of the Ratios of Branching Fractions R(D^{*}) and R(D^{0})

LHCb Collaboration

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The ratios of branching fractions R(D^{*})≡B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}μ^{-}ν[over ¯]_{μ}) and R(D^{0})≡B(B^{-}→D^{0}τ^{-}ν[over ¯]_{τ})/B(B^{-}→D^{0}μ^{-}ν[over ¯]_{μ}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0  fb^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ^{-}→μ^{-}ν_{τ}ν[over ¯]_{μ}. The measured values are R(D^{*})=0.281±0.018±0.024 and R(D^{0})=0.441±0.060±0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=-0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model.

Original languageEnglish
Article number111802
Pages (from-to)1-13
Number of pages13
JournalPhysical review letters
Volume131
Issue number11
Early online date13 Sept 2023
DOIs
Publication statusPublished - 15 Sept 2023

Funding

We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ, and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG, and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MCID/IFA (Romania); MICINN (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); DOE NP and NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), Polish WLCG (Poland) and NERSC (USA). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from ARC and ARDC (Australia); Minciencias (Colombia); AvH Foundation (Germany); EPLANET, Marie Skłodowska-Curie Actions and ERC (European Union); A*MIDEX, ANR, IPhU and Labex P2IO, and Région Auvergne-Rhône-Alpes (France); Key Research Program of Frontier Sciences of CAS, CAS PIFI, CAS CCEPP, Fundamental Research Funds for the Central Universities, and Sci. & Tech. Program of Guangzhou (China); GVA, XuntaGal, GENCAT, and Prog. Atracción Talento, CM (Spain); SRC (Sweden); the Leverhulme Trust, the Royal Society, and UKRI (United Kingdom).

FundersFunder number
CAS CCEPP
EPLANET
Key Research Program of Frontier Sciences of CAS
National Science Foundation
Alexander von Humboldt-Stiftung
Nuclear Physics
Automotive Research Center
H2020 Marie Skłodowska-Curie Actions
CERN
Science and Technology Facilities Council
European Research Council
Deutsche Forschungsgemeinschaft
Agence Nationale de la Recherche
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
National Natural Science Foundation of China
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Bundesministerium für Bildung und Forschung
Chinese Academy of Sciences
Ministry of Science and Technology of the People's Republic of China
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Instituto Nazionale di Fisica Nucleare
Narodowe Centrum Nauki
Ministerstwo Edukacji i Nauki
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
National Academy of Sciences of Ukraine
Centre National de la Recherche Scientifique
Financiadora de Estudos e Projetos
Ministerio de Ciencia e Innovación
Région Auvergne-Rhône-Alpes
Fundamental Research Funds for the Central Universities
Institut national de physique nucléaire et de physique des particules
Sociedad Española de Reumatología
Australian Research Data Commons

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