Measurement of the Ratio of the B0→D*−τ+ντ and B0→D*−μ+νμ Branching Fractions Using Three-Prong τ -Lepton Decays
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PhysRevLett.120.171802.pdf
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Author(s)
Aaij, R.
Adeva, B.
Adinolfi, M.
Ajaltouni, Z.
Akar, S.
Albrecht, J.
Alessio, F.
Alexander, M.
Alfonso Albero, A.
Ali, S.
Date Issued
April 2018
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Aaij, R. et al. "Measurement of the Ratio of the B0→D*−τ+ντ and B0→D*−μ+νμ Branching Fractions Using Three-Prong τ -Lepton Decays." Physical Review Letters 120, 17 (April 2018): 171802 © 2018 CERN, for the LHCb Collaboration
Version
Final published version
Abstract
The ratio of branching fractions R(D*⁻)≡B(B⁰→D*⁻τ⁺ν[subscript τ])/B(B⁰→D*⁻μ⁺ν[subscript μ]) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb⁻¹. For the first time, R(D*⁻) is determined using the τ-lepton decays with three charged pions in the final state. The B^{0}→D*⁻τ⁺ν[subscript τ] yield is normalized to that of the B⁰→D*⁻π⁺π⁻π⁺ mode, providing a measurement of B(B⁰→D*⁻τ⁺ν[subscript τ])/B(B⁰→D*⁻π⁺π⁻π⁺)=1.97±0.13±0.18, where the first uncertainty is statistical and the second systematic. The value of B(B⁰→D^{*-}τ⁺ν[subscript τ])=(1.42±0.094±0.129±0.054)% is obtained, where the third uncertainty is due to the limited knowledge of the branching fraction of the normalization mode. Using the well-measured branching fraction of the B⁰→D*⁻μ⁺ν[subscript μ] decay, a value of R(D*⁻)=0.291±0.019±0.026±0.013 is established, where the third uncertainty is due to the limited knowledge of the branching fractions of the normalization and B⁰→D*⁻μ⁺ν[subscripts μ] modes. This measurement is in agreement with the standard model prediction and with previous results.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
http://dx.doi.org/10.1103/PhysRevLett.120.171802
