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 $\Delta A_{CP}$ 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 $D^+\to K^+\bar{K}^0$.