Search for CP Violation in the Decays $D^0\rightarrow K^0_S P^0$

TL;DR

This study searches for CP violation in specific D0 meson decays using Belle detector data, finding no significant CP asymmetry but providing the most precise measurement for some decay modes and first measurements for others.

Contribution

It provides the most precise CP asymmetry measurement in D0→K0_Sπ0 decay and the first measurements in D0→K0_Sη and D0→K0_Sη' decays, expanding experimental constraints on CP violation.

Findings

No significant CP violation observed.

Most precise measurement for D0→K0_Sπ0.

First measurements for D0→K0_Sη and D0→K0_Sη'.

Abstract

We have searched for CP violation in the decays $D^0\rightarrow K^0_S P^0$ where $P^0$ denotes a neutral pseudo-scalar meson which is either a $\pi^0$, $\eta$, or $\eta'$ using KEKB asymmetric-energy $e^+e^-$ collision data corresponding to an integrated luminosity of 791 fb$^{-1}$ collected with the Belle detector. No evidence of significant CP violation is observed. We report the most precise CP asymmetry measurement in the decay $D^0\rightarrow K^0_S\pi^0$ to date: $A_{CP}^{D^0\rightarrow K^0_S\pi^0}=(-0.28\pm0.19\pm0.10)%$. We also report the first measurements of CP asymmetries in the decays $D^0\rightarrow K^0_S\eta$ and $D^0\rightarrow K^0_S\eta'$: $A_{CP}^{D^0\rightarrow K^0_S\eta}=(+0.54\pm0.51\pm0.16)%$ and $A_{CP}^{D^0\rightarrow K^0_S\eta'}=(+0.98\pm0.67\pm0.14)%$, respectively.