PRD 87, 071103(R) (2013)

LHCb: INSPIRE

ParameterMeasurement
\(\frac{{\cal{B}} ( B_c^- \to \psi(2S) \pi^- ) } {{\cal{B}} ( B_c^- \to J/\psi \pi^- ) }\)\([0.25 \pm 0.07\mbox{ (stat)} \pm 0.01\mbox{ (syst)} \pm 0.01\mbox{ (R(psi))}]\)