Dalitz analysis of the decayD0→K−π+π0

We use data collected with the CLEO II detector to perform a high-statistics measurement of the resonant substructure in $D^0\to K^{-}{\pi }^{+}{\pi }^0$ decays. We find that the Dalitz plot is well represented by a combination of seven quasi-two-body decay channels $[K^{*0}{\pi }^0,K^{-}\rho ,K^{*-}{\pi }^{+},K_0{\mathrm{}\left(1430\right)\mathrm{}}^{-}{\pi }^{+},K_0{\mathrm{}\left(1430\right)\mathrm{}}^0{\pi }^0,K^{-}{\rho }^{+}\mathrm{}(1700),$ and $K^{*}{\mathrm{}\left(1680\right)\mathrm{}}^{-}{\pi }^{+}],$ plus a small non-resonant component. We see no evidence of a scalar $\overrightarrow{\kappa }{K}^{-}{\pi }^{+}$ resonance in the mass range recently reported by other groups. Using the amplitudes and phases from this analysis, we calculate an integrated $\mathrm{CP}$ asymmetry of $-0.031\pm \mathrm{0.086.}$