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

TL;DR

This study searches for $CP$ violation in the decay $D^{+} o ext{ extpi}^{+} ext{ extpi}^{0}$ using Belle data, finding results consistent with the standard model and improving measurement precision.

Contribution

First precise measurement of $CP$ violation in $D^{+} o ext{ extpi}^{+} ext{ extpi}^{0}$ decay with Belle, enhancing sensitivity to new physics.

Findings

Measured $CP$ asymmetry: $+2.31 ext{ extpm}1.24 ext{(stat)} ext{ extpm}0.23 ext{(syst)}\\%$

Results consistent with standard model predictions

Significantly improved measurement precision

Abstract

We search for $CP$ violation in 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 experiment at the KEKB $e^{+}e^{-}$ asymmetric-energy collider. The measured $CP$ violating asymmetry 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.