Measurement of the branching fractions for inclusive $B^{-}$ and ${\overline{B}}^0$ decays to flavor-tagged $D$, $D_s$, and ${\Lambda }_c$

We report on the inclusive branching fractions of $B^{-}$ and of ${\overline{B}}^0$ mesons decaying to $D^{0}X$, ${\overline{D}}^{0}X$, $D^{+}X$, $D^{-}X$, $D_s^{+}X$, $D_s^{-}X$, ${\Lambda }_c^{+}X$, ${\overline{\Lambda }}_c^{-}X$, based on a sample of $88.9\times {10}^6$ $B\overline{B}$ events recorded with the BABAR detector at the ${\rm Y}(4S)$ resonance. Events are selected by completely reconstructing one $B$ and searching for a reconstructed charmed particle in the rest of the event. We measure the number of charmed and of anticharmed particles per $B$ decay and derive the total charm yield per $B^{-}$ decay $n_c^{-}=1.313\pm 0.037\pm {0.062}_{-0.042}^{+0.063}$ and per ${\overline{B}}^0$ decay $n_c^0=1.276\pm 0.062\pm {0.058}_{-0.046}^{+0.066}$, where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties.

Figure 1

$m_{\mathrm{E}\mathrm{S}}$ spectra of reconstructed (a) $B^{+}$ and (b) $B^0$ candidates. The solid vertical line shows the upper limit of the background control region (hatched), the dotted vertical line the lower limit of the $B$ signal region. The crossed area shows the background under the $B$ signal. The solid curve is the sum of the fitted signal and background; the dashed curve is the background component only.

Figure 2

Correlated (left) and anticorrelated (right) charmed-particle mass spectra in the recoil of $B^{+}$ events, for (a),(b) $D^0\to K^{-}{\pi }^{+}$; (c),(d) $D^{+}\to K^{-}{\pi }^{+}{\pi }^{+}$; (e),(f) $D_s^{+}\to \varphi {\pi }^{+}$; and (g),(h) ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$. The solid curve is the sum of a Gaussian signal and of a linear background plus mode-dependent satellite contributions [17]. The shaded areas show the contribution of well reconstructed $D$, $D_s$, or ${\Lambda }_c$ in the $B^{+}$ combinatorial background.