We report the discovery of ${\mathrm{\Xi }}_c(3055{)}^0$, observed by its decay into the final-state $\mathrm{\Lambda }{D}^0$, and present the first observation and evidence of the decays of ${\mathrm{\Xi }}_c(3055{)}^{+}$ and ${\mathrm{\Xi }}_c(3080{)}^{+}$ into $\mathrm{\Lambda }{D}^{+}$. We also perform a combined analysis of the $\mathrm{\Lambda }{D}^{+}$ with the ${\mathrm{\Sigma }}_c^{++}{K}^{-}$ and ${\mathrm{\Sigma }}_c^{*++}{K}^{-}$ decay modes to measure the ratios of branching fractions, masses and widths with improved accuracy. We measure the ratios of branching fractions $\mathcal{B}({\mathrm{\Xi }}_c(3055{)}^{+}\to \mathrm{\Lambda }{D}^{+})/\mathcal{B}({\mathrm{\Xi }}_c(3055{)}^{+}\to {\mathrm{\Sigma }}_c^{++}{K}^{-})=5.09\pm 1.01\pm 0.76$, $\mathcal{B}({\mathrm{\Xi }}_c(3080{)}^{+}\to \mathrm{\Lambda }{D}^{+})/\mathcal{B}({\mathrm{\Xi }}_c(3080{)}^{+}\to {\mathrm{\Sigma }}_c^{++}{K}^{-})=1.29\pm 0.30\pm 0.15$, and $\mathcal{B}({\mathrm{\Xi }}_c(3080{)}^{+}\to {\mathrm{\Sigma }}_c^{*++}{K}^{-})/\mathcal{B}({\mathrm{\Xi }}_c(3080{)}^{+}\to {\mathrm{\Sigma }}_c^{++}{K}^{-})=1.07\pm 0.27\pm 0.04$, where the uncertainties are statistical and systematic. The analysis is performed using a $980{\mathrm{fb}}^{-1}$ data sample collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider.

• Received 30 May 2016

DOI:https://doi.org/10.1103/PhysRevD.94.032002