@article{3e2c0281a1804970959158879cb6833d,

title = "Measurement of the Ratio of Branching Fractions B (Bc+ →j /ψτ+ντ)/ B (Bc+ →j /ψμ+νμ)",

abstract = "A measurement is reported of the ratio of branching fractions R(J/ψ)=B(Bc+→J/ψτ+ντ)/B(Bc+→J/ψμ+νμ), where the τ+ lepton is identified in the decay mode τ+→μ+νμντ. 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 Bc+→J/ψτ+ντ 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.",

author = "R. Aaij and B. Adeva and M. Adinolfi and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and {Alfonso Albero}, A. and S. Ali and G. Alkhazov and {Alvarez Cartelle}, P. and Alves, {A. A.} and S. Amato and S. Amerio and Y. Amhis and L. An and L. Anderlini and G. Andreassi and M. Andreotti and Andrews, {J. E.} and Appleby, {R. B.} and F. Archilli and P. D'Argent and {Arnau Romeu}, J. and A. Artamonov and M. Artuso and E. Aslanides and M. Atzeni and G. Auriemma and M. Baalouch and I. Babuschkin and S. Bachmann and Back, {J. J.} and {Carvalho Akiba}, K. and {De Bruyn}, K. and M. Ferro-Luzzi and T. Ketel and T. Li and M. Merk and Onderwater, {C. J.G.} and G. Raven and M. Schiller and N. Serra and B. Storaci and V. Syropoulos and {Van Tilburg}, J. and S. Tolk and P. Tsopelas and N. Tuning and {(LHCb Collaboration)}",

year = "2018",

month = mar,

day = "23",

doi = "10.1103/PhysRevLett.120.121801",

language = "English",

volume = "120",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "12",

}