Measurement of the Ratio of Branching Fractions β(B+c⁺ → J/ψτ⁺ντ)/β(B⁺c → J/ψμ⁺νμ)
Name
PhysRevLett.120.121801.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
March 2018
Journal
Physical Review Letters
Publisher
American Physical Society
Version
Final published version
Abstract
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.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Department of Physics
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Creative Commons Attribution 3.0 unported license
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DOI of Published Version
http://dx.doi.org/10.1103/PhysRevLett.120.121801
