We present the first measurements of absolute branching fractions of ${\mathrm{\Xi }}_c^0$ decays into ${\mathrm{\Xi }}^{-}{\pi }^{+}$, $\mathrm{\Lambda }{K}^{-}{\pi }^{+}$, and $p{K}^{-}{K}^{-}{\pi }^{+}$ final states. The measurements are made using a dataset comprising $(772\pm 11)\times {10}^6$ $B\overline{B}$ pairs collected at the $\mathrm{\Upsilon }(4S)$ resonance with the Belle detector at the KEKB $e^{+}{e}^{-}$ collider. We first measure the absolute branching fraction for $B^{-}\to {\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Xi }}_c^0$ using a missing-mass technique; the result is $\mathcal{B}(B^{-}\to {\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Xi }}_c^0)=(9.51\pm 2.10\pm 0.88)\times {10}^{-4}$. We subsequently measure the product branching fractions $\mathcal{B}(B^{-}\to {\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Xi }}_c^0)\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+})$, $\mathcal{B}(B^{-}\to {\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Xi }}_c^0)\mathcal{B}({\mathrm{\Xi }}_c^0\to \mathrm{\Lambda }{K}^{-}{\pi }^{+})$, and $\mathcal{B}(B^{-}\to {\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Xi }}_c^0)\mathcal{B}({\mathrm{\Xi }}_c^0\to p{K}^{-}{K}^{-}{\pi }^{+})$ with improved precision. Dividing these product branching fractions by the result for $B^{-}\to {\overline{\mathrm{\Lambda }}}_c^{-}{\mathrm{\Xi }}_c^0$ yields the following branching fractions: $\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+})=(1.80\pm 0.50\pm 0.14)\%$, $\mathcal{B}({\mathrm{\Xi }}_c^0\to \mathrm{\Lambda }{K}^{-}{\pi }^{+})=(1.17\pm 0.37\pm 0.09)\%$, and $\mathcal{B}({\mathrm{\Xi }}_c^0\to p{K}^{-}{K}^{-}{\pi }^{+})=(0.58\pm 0.23\pm 0.05)\%$. For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for $\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+})$ can be combined with ${\mathrm{\Xi }}_c^0$ branching fractions measured relative to ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}$ to yield other absolute ${\mathrm{\Xi }}_c^0$ branching fractions.

• Received 24 November 2018
• Revised 27 January 2019

DOI:https://doi.org/10.1103/PhysRevLett.122.082001

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Published by the American Physical Society