Search forCPviolation inD0→KS0π+π−

We report on a search for $CP$ violation in the decay of $D^0$ and ${\overline{D}}^0$ to $K_S^0{\pi }^{+}{\pi }^{-}$. The data come from an integrated luminosity of $9.0{\mathrm{f}\mathrm{b}}^{-1}$ of $e^{+}{e}^{-}$ collisions at $\sqrt{s}\approx 10\mathrm{G}\mathrm{e}\mathrm{V}$ recorded with the CLEO II.V detector. The resonance substructure of this decay is well described by ten quasi-two-body decay channels plus a small nonresonant component. We observe no evidence for $CP$ violation in the amplitudes that describe the decay $D^0\to K_S^0{\pi }^{+}{\pi }^{-}$.