Study of CP Violation in Flavor Tagged and Untagged $D^0 \rightarrow   K^-\pi^+$ Decays
  We review $CP$-violating observables in flavor tagged and untagged $D^0 \rightarrow K^{-}\pi^{+}$ decays and evaluate the $CP$ asymmetry difference between the two decays. We note that this commonly neglected difference is not zero in principle and can be significant in future $B$ factory experiments. We also construct an expression to extract the strong phase difference between $\bar{D}^0 \rightarrow K^-\pi^+$ and $D^0 \rightarrow K^-\pi^+$ decays, independently of existing experimental methods. 
E. Won, B. R. Ko, and B. Golob
hep-ex hep-ph