Measurement of the ratio of branching fractions ℬ(B_c⁺ → J/ψτ⁺ ν_τ)/ℬ(B_c⁺ → J/ψμ⁺ ν_μ)

@misc{collaboration2026measurement,
  title = {{Measurement of the ratio of branching fractions $\mathcalB(B_c^+ \to J/ψτ^+ ν_τ)/\mathcalB(B_c^+ \to J/ψμ^+ ν_μ)$}},
  author = {LHCb collaboration and R. Aaij and M. Abdelfatah and A. S. W. Abdelmotteleb and C. Abellan Beteta and F. Abudinén and T. Ackernley and A. A. Adefisoye and B. Adeva and M. Adinolfi and P. Adlarson and C. Agapopoulou and C. A. Aidala and S. Akar and K. Akiba and H. Al Saleh and P. Albicocco and J. Albrecht and R. Aleksiejunas and F. Alessio and P. Alvarez Cartelle and S. Amato and J. L. Amey and Y. Amhis and L. An and L. Anderlini and M. Andersson and P. Andreola and M. Andreotti and S. Andres Estrada and A. Anelli and D. Ao and C. Arata and F. Archilli and Z. Areg and M. Argenton and S. Arguedas Cuendis and L. Arnone and M. Artuso and E. Aslanides and R. Ataíde Da Silva and M. Atzeni and B. Audurier and J. A. Authier and D. Bacher and I. Bachiller Perea and S. Bachmann and M. Bachmayer and J. J. Back and Z. B. Bai and V. Balagura and A. Balboni and W. Baldini and Z. Baldwin and L. Balzani and H. Bao and J. Baptista de Souza Leite and C. Barbero Pretel and M. Barbetti and I. R. Barbosa},
  howpublished = {arXiv},
  year = {2026},
  month = oct,
  doi = {10.48550/arxiv.2606.10018},
  eprint = {2606.10018},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2606.10018},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Measurement of the ratio of branching fractions ℬ(B_c^+ → J/ψτ^+ ν_τ)/ℬ(B_c^+ → J/ψμ^+ ν_μ)
AU  - LHCb collaboration
AU  - R. Aaij
AU  - M. Abdelfatah
AU  - A. S. W. Abdelmotteleb
AU  - C. Abellan Beteta
AU  - F. Abudinén
AU  - T. Ackernley
AU  - A. A. Adefisoye
AU  - B. Adeva
AU  - M. Adinolfi
AU  - P. Adlarson
AU  - C. Agapopoulou
AU  - C. A. Aidala
AU  - S. Akar
AU  - K. Akiba
AU  - H. Al Saleh
AU  - P. Albicocco
AU  - J. Albrecht
AU  - R. Aleksiejunas
AU  - F. Alessio
AU  - P. Alvarez Cartelle
AU  - S. Amato
AU  - J. L. Amey
AU  - Y. Amhis
AU  - L. An
AU  - L. Anderlini
AU  - M. Andersson
AU  - P. Andreola
AU  - M. Andreotti
AU  - S. Andres Estrada
AU  - A. Anelli
AU  - D. Ao
AU  - C. Arata
AU  - F. Archilli
AU  - Z. Areg
AU  - M. Argenton
AU  - S. Arguedas Cuendis
AU  - L. Arnone
AU  - M. Artuso
AU  - E. Aslanides
AU  - R. Ataíde Da Silva
AU  - M. Atzeni
AU  - B. Audurier
AU  - J. A. Authier
AU  - D. Bacher
AU  - I. Bachiller Perea
AU  - S. Bachmann
AU  - M. Bachmayer
AU  - J. J. Back
AU  - Z. B. Bai
AU  - V. Balagura
AU  - A. Balboni
AU  - W. Baldini
AU  - Z. Baldwin
AU  - L. Balzani
AU  - H. Bao
AU  - J. Baptista de Souza Leite
AU  - C. Barbero Pretel
AU  - M. Barbetti
AU  - I. R. Barbosa
PY  - 2026
DA  - 2026/10/01
PB  - arXiv
DO  - 10.48550/arxiv.2606.10018
UR  - https://arxiv.org/abs/2606.10018
AB  - A measurement of the ratio of semileptonic branching fractions ℛ(Jψ), defined as ℛ(J/ψ) ≡ ℬ(B_c^+ → J/ψτ^+ ν_τ)/ℬ(B_c^+ → J/ψμ^+ ν_μ), is reported using a sample of proton-proton collision data corresponding to an integrated luminosity of 5.4 fb^−1 recorded by the LHCb experiment in 2016--2018 at a center-of-mass energy of 13 TeV. The measured value is found to be ℛ(J/ψ) = 0.51 ± 0.12(stat) ± 0.08(syst), which is within 1.8 standard deviations of the predictions from the Standard Model assuming lepton flavor universality.
ER  -