PT Journal
AU LHCb Collaboration (Aaij, Rea
   Garcia Martin, LM
   Henry, L
   Martinez-Vidal, F
   Oyanguren, A
   Remon Alepuz, C
   Ruiz Valls, P
   Ruiz Vidal, J
   Sanchez Mayordomo, C
TI Measurement of the Ratio of Branching Fractions B(B-c(+) -> J/psi tau(+)nu(tau))/B(B-c(+) -> J/psi mu(+)nu(mu))
SO Physical Review Letters
JI Phys. Rev. Lett.
PY 2018
BP 121801 - 10pp
VL 120
IS 12
DI 10.1103/PhysRevLett.120.121801
LA English
AB A measurement is reported of the ratio of branching fractions R(J/psi) = B(B-c(+) -> J/psi tau(+)nu(tau))/B(B-c(+) -> J/psi mu(+)nu(mu)), where the tau(+) lepton is identified in the decay mode tthorn tau(+) -> mu(+)nu(mu)(nu) over bar (tau). 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/psi tau(+)nu(tau) at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R(J/psi) = 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.
ER