Measurement ofϕ3with Dalitz plot analysis ofB±→D(*)K±decay

We present a measurement of the unitarity triangle angle ${\varphi }_3$ using a Dalitz plot analysis of the three-body decay of the neutral $D$ meson from the $B^{\pm }\to D^{(*)}{K}^{\pm }$ process. The method employs the interference between $D^0$ and $\overline{D^0}$ to extract both the weak and strong phases. We apply this method to a $140{\mathrm{f}\mathrm{b}}^{-1}$ data sample collected by the Belle experiment. The analysis uses the modes $B^{\pm }\to D{K}^{\pm }$ and $B^{\pm }\to D^{*}{K}^{\pm }$, $D^{*}\to D{\pi }^0$, where the neutral $D$ meson decays into $K_S{\pi }^{+}{\pi }^{-}$. We obtain 146 signal candidates for $B^{\pm }\to D{K}^{\pm }$ and 39 candidates for $B^{\pm }\to D^{*}{K}^{\pm }$. From a combined maximum likelihood fit to the $B^{\pm }\to D{K}^{\pm }$ and $B^{\pm }\to D^{*}{K}^{\pm }$ modes, we obtain ${\varphi }_3=77°\genfrac{}{}{0ex}{}{+17°}{-19°}(\mathrm{\text{stat}})\pm 13°(\mathrm{\text{syst}})\pm 11°(\mathrm{\text{model}})$. The corresponding 2 standard deviation interval is $26°<{\varphi }_3<126°$.