Search for $CP$ violation in $D_{(s)}^{+}\to K^{+}{K}_S^0{h}^{+}{h}^{-}$ $(h=K,\pi )$ decays and observation of the Cabibbo-suppressed decay $D_s^{+}\to K^{+}{K}^{-}{K}_S^0{\pi }^{+}$

Abstract

We search for $CP$ violation by measuring a $T$-odd asymmetry in the Cabibbo-suppressed $D^{+}\to K^{+}{K}_S^0{\pi }^{+}{\pi }^{-}$ decay, and in the Cabibbo-favored $D_s^{+}\to K^{+}{K}_S^0{\pi }^{+}{\pi }^{-}$ and $D^{+}\to K^{+}{K}^{-}{K}_S^0{\pi }^{+}$ decays. We use 980 ${\mathrm{fb}}^{-1}$ of data collected by the Belle detector running at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The $CP$-violating $T$-odd parameter $a_{CP}^{T\text{-}\mathrm{odd}}$ is measured to be $a_{CP}^{T\text{-}\mathrm{odd}}(D^{+}\to K^{+}{K}_S^0{\pi }^{+}{\pi }^{-})=(0.34\pm 0.87\pm 0.32)\%,$ $a_{CP}^{T\text{-}\mathrm{odd}}(D_s^{+}\to K^{+}{K}_S^0{\pi }^{+}{\pi }^{-})=(-0.46\pm 0.63\pm 0.38)\%,$ and $a_{CP}^{T\text{-}\mathrm{odd}}(D^{+}\to K^{+}{K}^{-}{K}_S^0{\pi }^{+})=(-3.34\pm 2.66\pm 0.35)\%,$ where the first uncertainty is statistical and the second is systematic. We also report the first observation of the Cabibbo-suppressed decay $D_s^{+}\to K^{+}{K}^{-}{K}_S^0{\pi }^{+}$. The branching fraction is measured relative to that of the analogous Cabibbo-favored decay : $B(D_s^{+}\to K^{+}{K}^{-}{K}_S^0{\pi }^{+})/B(D_s^{+}\to K^{+}{K}_S^0{\pi }^{+}{\pi }^{-})=(1.36\pm 0.15\pm 0.04)\%$.

References in corpus (6)

• Observation of $CP$ violation in charm decays
• New Physics and CP Violation in Singly Cabibbo Suppressed D Decays
• Dispersive and Absorptive CP Violation in $D^0-\overline{D^0}$ Mixing
• Measurement of the branching fractions for Cabibbo-suppressed decays $D^{+}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^0$ and $D_{(s)}^{+}\to K^{+}{\pi }^{-}{\pi }^{+}{\pi }^0$ at Belle
• Measurement of the branching fraction and search for $CP$ violation in $D^0\to K_S^0{K}_S^0{\pi }^{+}{\pi }^{-}$ decays at Belle
• Measurement of the branching fraction and search for CP violation in $D^0\to K_S^0{K}_S^0{\pi }^{+}{\pi }^{-}$ decays at Belle