PT Journal
AU LHCb Collaboration (Aaij, Rea
   Jaimes Elles, SJ
   Jashal, BK
   Martinez-Vidal, F
   Oyanguren, A
   Rebollo De Miguel, M
   Remon Alepuz, C
   Ruiz Vidal, J
   Sanderswood, I
TI Measurement of the Ratios of Branching Fractions R(D*) and R(D0)
SO Physical Review Letters
JI Phys. Rev. Lett.
PY 2023
BP 111802
EP 13pp
VL 131
IS 11
DI 10.1103/PhysRevLett.131.111802
LA English
AB The ratios of branching fractions R(D*) = B((B) over bar -> D* tau(-) (v) over bar (tau))/B((B) over bar -> D*.mu(-)(v) over bar mu) and R(D-0) = B(B- -> D(0)t-mu(-)(v) over bar mu) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb(-1) of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode tau(-) -> mu(-)v(tau)(v) over bar mu. The measured values are R(D) = 0.281 +/- 0.018 +/- 0.024 and R(D-0) = 0.441 +/- 0.060 +/- 0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is rho = -0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model.
ER