We report improved measurements of the product branching fractions $\mathcal{B}(B^{+}\to {\overline{D}}^0{D}_{s0}^{*+}(2317))\times \mathcal{B}(D_{s0}^{*+}(2317)\to D_s^{+}{\pi }^0)=(8.0_{-1.2}^{+1.3}\pm 1.1\pm 0.4)\times 10^{-4}$ and $\mathcal{B}(B^0\to D^{-}{D}_{s0}^{*+}(2317))\times \mathcal{B}(D_{s0}^{*+}(2317)\to D_s^{+}{\pi }^0)=(10.2_{-1.2}^{+1.3}\pm 1.0\pm 0.4)\times 10^{-4}$, where the first errors are statistical, the second are systematic and the third are from $D$ and $D_s^{+}$ branching fractions. In addition, we report negative results from a search for hypothesized neutral (${\mathbf{z}}^0$) and doubly charged (${\mathbf{z}}^{++}$) isospin partners of the $D_{s0}^{*+}(2317)$ and provide upper limits on the product branching fractions $\mathcal{B}(B^0\to D^0{\mathbf{z}}^0)\times \mathcal{B}({\mathbf{z}}^0\to D_s^{+}{\pi }^{-})$ and $\mathcal{B}(B^{+}\to D^{-}{\mathbf{z}}^{++})\times \mathcal{B}({\mathbf{z}}^{++}\to D_s^{+}{\pi }^{+})$ that are more than an order of magnitude smaller than theoretical expectations for the hypotheses that the $D_{s0}^{*+}(2317)$ is a member of an isospin triplet. The analysis uses a $711{\mathrm{fb}}^{-1}$ data sample containing 772 million $B\overline{B}$-meson pairs collected at the $\mathrm{\Upsilon }(4S)$ resonance in the Belle detector at the KEKB collider.

• Received 10 April 2015
• Corrected 18 August 2015

DOI:https://doi.org/10.1103/PhysRevD.91.092011