Search for CP Violation in the Decay $D^{+}\to K_S^0{K}^{+}$

We search for CP violation in the decay $D^{+}\to K_S^0{K}^{+}$ 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 $D^{+}\to K_S^0{K}^{+}$ decay is measured to be $(-0.25\pm 0.28\pm 0.14)$, which is the most sensitive measurement to date. After subtracting CP violation due to $K^0-{\bar{K}}^0$ mixing, the CP asymmetry in $D^{+}\to {\bar{K}}^0{K}^{+}$ decay is found to be $(+0.08\pm 0.28\pm 0.14)$.