JHEP09(2013)075

LHCb: INSPIRE

ParameterMeasurement
\( \frac{{\cal{B}}( B_c^- \to J/\psi K^-)} { {\cal{B}}( B_c^- \to J/\psi \pi^-)}\)\([0.069 \pm 0.019\mbox{ (stat)} \pm 0.005\mbox{ (syst)}]\)