Measurement of the doubly Cabibbo suppressed decay $D^0\to K^{+}{\pi }^{-}$ and a search for charm mixing

Abstract

We present an analysis of the decay $D^0\to K^{+}{\pi }^{-}$ based on FOCUS data. From a sample of 234 signal events, we find a branching ratio of $\frac{\Gamma (D^0\to K^{+}{\pi }^{-})}{\Gamma (D^0\to K^{-}{\pi }^{+})}=(0.429_{-0.061}^{+0.063}\pm 0.027)$ under the assumptions of no mixing and no CP violation. Allowing for CP violation, we find a branching ratio of $(0.429\pm 0.063\pm 0.028)$ and a \textit{CP} asymmetry of $0.18\pm 0.14\pm 0.04$. The branching ratio for the case of mixing with no CP violation is $(0.381_{-0.163}^{+0.167}\pm 0.092)$. We also present limits on charm mixing.

As accepted by Physics Letters B