CP violation in charm decays at Belle

TL;DR

This study searches for CP violation in charm meson decays at Belle, finding no evidence of CP violation but measuring asymmetries in specific decay channels with high precision.

Contribution

First comprehensive search for CP violation in multiple charm decay modes at Belle, including measurements of asymmetry differences with corrections for detector effects.

Findings

No evidence of CP violation observed.

Measured CP asymmetry differences with high precision.

Results consistent with Standard Model predictions.

Abstract

We have searched for CP violation of charmed mesons in the decays $D\to K^0_S P$, where $D$ denotes $D^0$ and $D^+_{(s)}$, and $P$ denotes the pseudo-scalar mesons $\pi^+$, $K^+$, $\pi^0$, $\eta$, and $\eta'$. No evidence of CP violation in these decays is observed. We also have measured the CP asymmetry difference between the Cabibbo suppressed decay $D^+\to\phi\pi^+$ and the Cabibbo favored $D^+_s\to\phi\pi^+$ decays in the region of $|M(K^+K^-)-M^{\phi}_{PDG}|<$16 MeV/$c^2$. The measured asymmetry is corrected for the residual asymmetry due to detector effects, and the contributions of both CP and forward-backward asymmetries are determined. These results are obtained on a large data sample collected at and near the $\Upsilon(4S)$ resonance with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider.