Search for CP Violation in the Decay $D^+\rightarrow K^0_S K^+$

TL;DR

This study searches for CP violation in the decay $D^+ ightarrow K^0_S K^+$ using a large data sample, finding no significant CP violation and providing the most sensitive measurement to date.

Contribution

The paper presents the most sensitive measurement of CP asymmetry in $D^+ ightarrow K^0_S K^+$ decay, improving previous limits and accounting for $K^0-ar{K}^0$ mixing effects.

Findings

No evidence of CP violation observed.

Measured CP asymmetry is $(-0.25 ext{±}0.28 ext{±}0.14)%$.

CP asymmetry after correction is $(+0.08 ext{±}0.28 ext{±}0.14)%$.

Abstract

We search for CP violation in the decay $D^+\rightarrow K^0_S K^+$ using a data sample with an integrated luminosity of 977 fb$^{-1}$ collected with the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. No CP violation has been observed and the CP asymmetry in $D^+\rightarrow K^0_S K^+$ decay is measured to be $(-0.25\pm0.28\pm0.14)%$, which is the most sensitive measurement to date. After subtracting CP violation due to $K^0-\bar{K}^0$ mixing, the CP asymmetry in $D^+\rightarrow\bar{K}^0 K^+$ decay is found to be $(+0.08\pm0.28\pm0.14)%$.