Measurement of the Ratio of Branching Fractions <i>B</i>(<i>B<sub>c</sub></i><SUP>+</SUP> → <i>J</i>/ψτ<SUP>+</SUP>ν<sub>τ</sub>)/<i>B</i>(<i>B<sub>c</sub></i><SUP>+</SUP> → <i>J</i>/ψμ<SUP>+</SUP>ν<sub>μ</sub>)

Aaij, R, Adeva, B, Adinolfi, M, Ajaltouni, Z, Akar, S, Albrecht, J, Alessio, F, Alexander, M, Alfonso Albero, A, Ali, S
et al (show 790 more authors) (2018) Measurement of the Ratio of Branching Fractions <i>B</i>(<i>B<sub>c</sub></i><SUP>+</SUP> → <i>J</i>/ψτ<SUP>+</SUP>ν<sub>τ</sub>)/<i>B</i>(<i>B<sub>c</sub></i><SUP>+</SUP> → <i>J</i>/ψμ<SUP>+</SUP>ν<sub>μ</sub>). PHYSICAL REVIEW LETTERS, 120 (12). 121801-.

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A measurement is reported of the ratio of branching fractions R(J/ψ)=B(B_{c}^{+}→J/ψτ^{+}ν_{τ})/B(B_{c}^{+}→J/ψμ^{+}ν_{μ}), where the τ^{+} lepton is identified in the decay mode τ^{+}→μ^{+}ν_{μ}ν[over ¯]_{τ}. This analysis uses a sample of proton-proton collision data corresponding to 3.0  fb^{-1} of integrated luminosity recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. A signal is found for the decay B_{c}^{+}→J/ψτ^{+}ν_{τ} at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R(J/ψ)=0.71±0.17(stat)±0.18(syst). This result lies within 2 standard deviations above the range of central values currently predicted by the standard model.

Item Type: Article
Additional Information: All figures and tables, along with any supplementary material and additional information, are available at
Uncontrolled Keywords: LHCb Collaboration
Depositing User: Symplectic Admin
Date Deposited: 08 May 2018 07:39
Last Modified: 14 Mar 2024 23:32
DOI: 10.1103/PhysRevLett.120.121801
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