Measurement of the Ratio of the <i>B</i><SUP>0</SUP> → <i>D*<SUP>-</SUP>ι<SUP>+</SUP>v<sub>ι</sub> and B</i><SUP>0</SUP> → <i>D*<SUP>-</SUP> μ<SUP>+</SUP>v<sub>μ</sub></i> Branching Fractions Using Three-Prong τ-Lepton Decays



Aaij, R, Adeva, B, Adinolfi, M, Ajaltouni, Z, Akar, S, Albrecht, J, Alessio, F, Alexander, M, Alfonso Albero, A, Ali, S
et al (show 800 more authors) (2018) Measurement of the Ratio of the <i>B</i><SUP>0</SUP> → <i>D*<SUP>-</SUP>ι<SUP>+</SUP>v<sub>ι</sub> and B</i><SUP>0</SUP> → <i>D*<SUP>-</SUP> μ<SUP>+</SUP>v<sub>μ</sub></i> Branching Fractions Using Three-Prong τ-Lepton Decays. PHYSICAL REVIEW LETTERS, 120 (17). 171802-.

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Abstract

The ratio of branching fractions R(D^{*-})≡B(B^{0}→D^{*-}τ^{+}ν_{τ})/B(B^{0}→D^{*-}μ^{+}ν_{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_{τ} yield is normalized to that of the B^{0}→D^{*-}π^{+}π^{-}π^{+} mode, providing a measurement of B(B^{0}→D^{*-}τ^{+}ν_{τ})/B(B^{0}→D^{*-}π^{+}π^{-}π^{+})=1.97±0.13±0.18, where the first uncertainty is statistical and the second systematic. The value of B(B^{0}→D^{*-}τ^{+}ν_{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 B^{0}→D^{*-}μ^{+}ν_{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 B^{0}→D^{*-}μ^{+}ν_{μ} modes. This measurement is in agreement with the standard model prediction and with previous results.

Item Type: Article
Additional Information: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-017.html
Uncontrolled Keywords: LHCb Collaboration
Depositing User: Symplectic Admin
Date Deposited: 13 Aug 2018 06:56
Last Modified: 18 Oct 2023 04:30
DOI: 10.1103/PhysRevLett.120.171802
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3024855