Study of $B^{\pm }\to D_{CP}{K}^{\pm }$ and $D_{CP}^{*}{K}^{\pm }$ decays

We report a study of the modes $B^{\pm }\to D{K}^{\pm }$ and $B^{\pm }\to D^{*}{K}^{\pm }$ where $D^{(*)}$ decays to $CP$ eigenstates. The data sample used contains $275\times {10}^{6}B\overline{B}$ events at the ${\rm Y}(4S)$ resonance collected by the Belle detector at the KEKB energy-asymmetric $e^{+}{e}^{-}$ collider. The $CP$ asymmetries obtained for $D_{CP}K$ are: ${\mathcal{A}}_1=0.06\pm 0.14(\mathrm{stat})\pm 0.05(\mathrm{sys})$, ${\mathcal{A}}_2=-0.12\pm 0.14(\mathrm{stat})\pm 0.05(\mathrm{sys})$ and for $D_{CP}^{*}K$: ${\mathcal{A}}_1^{*}=-0.20\pm 0.22(\mathrm{stat})\pm 0.04(\mathrm{sys})$, ${\mathcal{A}}_2^{*}=0.13\pm 0.30(\mathrm{stat})\pm 0.08(\mathrm{sys})$.

Figure 1

Feynman diagrams for $B^{-}\to D^0{K}^{-}$ and $B^{-}\to {\overline{D}}^0{K}^{-}$.

Figure 2

$\Delta E$ distributions for (top left) $B^{+}\to D_1{K}^{+}$, (top right) $B^{-}\to D_1{K}^{-}$, (bottom left) $B^{+}\to D_2{K}^{+}$, (bottom right) $B^{-}\to D_2{K}^{-}$. Points with error bars are the data and the solid lines show the fit results. The components of the fit are the background from $B$ meson decays (dotted line), the continuum background (dashed line), the signal $DK$ (left) and $D\pi$ (right).

Figure 3

$\Delta E$ distributions for (left) $B^{\pm }\to D_1^{*0}{K}^{\pm }$ and (right) $B^{\pm }\to D_2^{*0}{K}^{\pm }$. Points with error bars are the data and the solid lines show the fit results.