  We present an analysis of the decay $D^0 \to K^+\pi^-$ from FOCUS. From a
sample of 234 events we find a branching ratio of $\frac{\Gamma(D^0 \to
K^+\pi^-)}{\Gamma(D^0 \to K^-\pi^+)} = (0.430^{+0.062}_{-0.061}\pm 0.031)%$
under the assumption of no mixing and no CP violation. We also present limits
on charm mixing.

High Energy Physics - Experiment