Direct CP Violation in Nonleptonic Charm Decays

LHCb, CDF and most recently Belle have observed a large difference between direct CP asymmetries in $D^0\to K^{+}{K}^{-}$ and $D^0\to {\pi }^{+}{\pi }^{-}$. We use the measured value of $\mathrm{\Delta }{A}_{CP}$ to constrain the magnitude and strong phase of a QCD-enhanced standard model penguin and predict its effects on direct CP asymmetry in $D^0\to {\pi }^0{\pi }^0$ and $D^{+}\to K^{+}{\bar{K}}^0$.