Search for CP violation in the D+→π+π0 decay at Belle

We search for $ CP$ violationin the charged charm meson decay $D^{+}\to\pi^{+}\pi^{0}$, based on a data sample corresponding to an integrated luminosity of $\rm 921~fb^{-1}$ collected by the Belle experimentat the KEKB$e^{+}e^{-}$ asymmetric-energy collider. The measured $ CP$ violatingasymmetry is $[+2.31\pm1.24({\rm stat})\pm0.23({\rm syst})]\%$, which is consistent with the standard model prediction and has a significantly improved precision compared to previous results.