Study of the Decay ${\mathit{D}}^0\to {\mathit{K}}^{+}{\mathit{\pi }}^{-}$

Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay $D^0\to K^{+}{\pi }^{-}$ with a signal yield of $149\pm 31$ events compared to a similarly cut sample consisting of $36760\pm 195$ $D^0\to K^{-}{\pi }^{+}$ events. We use the observed ratio of $D^0\to K^{+}{\pi }^{-}$ to $D^0\to K^{-}{\pi }^{+}$ $(0.404\pm 0.085\pm 0.025)\%$ to obtain a relationship between the $D^0$ mixing and doubly Cabibbo suppressed decay parameters.