Search for $CP$ violation in the $D^{+}topi^{+}pi^{0}$ decay at Belle

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