PRL 103, 191802 (2009)

CDF: INSPIRE link

ParameterMeasurement
\(\frac{{\cal{B}} ( \bar{B}_s^0 \to D_s^+ K^- )}{{\cal{B}} ( \bar{B}_s^0 \to D_s^+ \pi^- )}\)\([0.097 \pm 0.018\mbox{ (stat)} \pm 0.009\mbox{ (syst)}] \times 10^{0}\)