Study of the decays $B\to D_{s1}(2536{)}^{+}{\overline{D}}^{(*)}$

We report a study of the decays $B\to D_{s1}(2536{)}^{+}{\overline{D}}^{(*)}$, where ${\overline{D}}^{(*)}$ is ${\overline{D}}^0$, $D^{-}$ or $D^{*-}$, using a sample of $657\times {10}^{6}B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The branching fractions of the decays $B^{+}\to D_{s1}(2536{)}^{+}{\overline{D}}^0$, $B^0\to D_{s1}(2536{)}^{+}{D}^{-}$ and $B^0\to D_{s1}(2536{)}^{+}{D}^{*-}$ multiplied by that of $D_{s1}(2536{)}^{+}\to (D^{*0}{K}^{+}+D^{*+}{K}^0)$ are found to be $(3.97\pm 0.85\pm 0.56)\times {10}^{-4}$, $(2.75\pm 0.62\pm 0.36)\times {10}^{-4}$ and $(5.01\pm 1.21\pm 0.70)\times {10}^{-4}$, respectively. The ratio $\mathcal{B}(D_{s1}\to D^{*0}{K}^{+})/\mathcal{B}(D_{s1}\to D^{*+}{K}^0)$ is measured to be $0.88\pm 0.24\pm 0.08$.

Figure 1

The scatter plot of $\Delta E$ vs $M_{\mathrm{bc}}$ (left), where (a) is the signal region and (b) is the sideband, and projections on $\Delta E$ for events with $M_{\mathrm{bc}}>5.27\mathrm{GeV}/c^2$ (center) and $M_{\mathrm{bc}}$ for events with $|\Delta E|<0.02\mathrm{GeV}$ (right). The $M_{\mathrm{bc}}$ distribution is parametrized with a single Gaussian for the signal and an ARGUS function [11] for the background. The $\Delta E$ is parametrized with a double Gaussian and a linear polynomial for the signal and background, respectively. The results of the fits are shown by the superimposed curves.

Figure 2

$D_{s1}(2536{)}^{+}$ mass distributions for: a), b), c) $B^{+}\to D_{s1}(2536{)}^{+}{\overline{D}}^0$; d), e), f) $B^0\to D_{s1}(2536{)}^{+}{D}^{-}$ and g), h), i) $B^0\to D_{s1}(2536{)}^{+}{D}^{*-}$ final states, followed by $D_{s1}(2536{)}^{+}$ decays to a), d), g) $D^{*0}(D^0\gamma )K^{+}$; b), e), h) $D^{*0}(D^0{\pi }^0)K^{+}$ and c), f), i) $D^{*+}(D^0{\pi }^{+})K_S^0$. The points with error bars are the data, while the curves show the fit result.