Evidence for CP Violation in the Decay $D^+rightarrow K^0_Spi^+$

We observe evidence for CP violation in the decay $D^+rightarrow K^0_Spi^+$ using a data sample with an integrated luminosity of 977 fb$^{-1}$ collected by the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. The CP asymmetry in the decay is measured to be $(-0.363pm0.094pm0.067)%$, which is 3.2 standard deviations away from zero, and is consistent with the expected CP violation due to the neutral kaon in the final state.