Observation of the decays $B^{+} \to \Sigma_{c}(2455)^{++} \bar{\Xi}_{c}^{\prime-}$ and $B^{0} \to \Sigma_{c}(2455)^{0} \bar{\Xi}_{c}^{\prime0}$
| Abstract | We report the first observation of the decays $B^{+} \to \Sigma_{c}(2455)^{++} \bar{\Xi}_{c}^{\prime-}$ and $B^{0} \to \Sigma_{c}(2455)^{0} \bar{\Xi}_{c}^{\prime0}$ with significances of $6.4\sigma$ and $5.3\sigma$, respectively, including statistical and systematic uncertainties. This analysis is based on data samples containing $771.6 \times 10^{6}$ and $520.6 \times 10^{6}$ $\Upsilon(4S)$ decays collected with the Belle detector at the KEKB collider and the Belle~II detector at the SuperKEKB collider. The branching fractions are measured to be $\mathcal{B}(B^+ \to \Sigma_c(2455)^{++} \bar{\Xi}_c^{\prime -}) = (1.68 \pm 0.31 \pm 0.12^{+1.49}_{-0.54}) \times 10^{-3}$ and $\mathcal{B}(B^0 \to \Sigma_c(2455)^{0} \bar{\Xi}_c^{\prime 0}) = (1.28 \pm 0.32 \pm 0.10^{+0.30}_{-0.21}) \times 10^{-3}$, where the first and second uncertainties are statistical and systematic, respectively, and the third arise from the uncertainties in the absolute branching fractions of $\bar{\Xi}_{c}^{-}$ and $\bar{\Xi}_{c}^{0}$ decays. This result represents the first observation of $B$-meson decays into a pair of charmed baryon--antibaryon states, each belonging to the $SU(3)$ flavor sextet. |
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| Tags | Belle Run 1 Run 2 (partial) |
| Working group | B Hadronic |
| Principal authors | @ Yang Li, Chengping Shen |
| Reference | submitted to PRD |
| Links | arXiv:2606.12905, |
Distributions of $\Delta E$ for the reconstructed (left) $B^{+} \to \Sigma_{c}(2455)^{++} \bar{\Xi}_{c}^{\prime-}$ and (right) $B^{0} \to \Sigma_{c}(2455)^{0} \bar{\Xi}_{c}^{\prime0}$ candidates in the (top) signal and (bottom) sideband regions of $M(\gamma \bar{\Xi}_{c}^{-,0})$ in the combined Belle and Belle~II data. Points with error bars denote the data. The blue and red solid curves represent the total fit results and fitted signal components, respectively, while the magenta and green shaded histograms represent the fitted SCF and combinatorial background components.
Distributions of (top) $M(\Lambda_{c}^{+}\pi^{\pm})$ and (bottom) $M(\gamma\bar{\Xi}_{c}^{-,0})$ for the reconstructed (left) $B^{+} \to \Sigma_{c}(2455)^{++} \bar{\Xi}_{c}^{\prime-}$ and (right) $B^{0} \to \Sigma_{c}(2455)^{0} \bar{\Xi}_{c}^{\prime0}$ candidates in the combined Belle and Belle~II data. Points with error bars represent the data. The magenta arrows indicate the defined signal regions for the $\Sigma_{c}(2455)^{++,0}$ and $\bar{\Xi}_{c}^{\prime-,0}$ candidates, while the green arrows indicate the corresponding sideband regions.
Diagram illustrating the internal $W$-emission topology for the decays $B^{+} \to \Sigma_{c}(2455)^{++} \bar{\Xi}_{c}^{\prime-}$ and $B^{0} \to \Sigma_{c}(2455)^{0} \bar{\Xi}_{c}^{\prime0}$, corresponding to $q = u$ and $q = d$, respectively.