The strong and radiative decays of the low-lying $S$- and $P$-wave ${\mathrm{\Lambda }}_{c(b)}$, ${\mathrm{\Sigma }}_{c(b)}$, ${\mathrm{\Xi }}_{c(b)}$, ${{\mathrm{\Xi }}_{c(b)}}^{\prime }$, and ${\mathrm{\Omega }}_{c(b)}$ baryons are systematically studied in a constituent quark model. We find that the radiative decay mode ${\mathrm{\Lambda }}_b^0\gamma$ could be very useful for us to establish the missing neutral states ${\mathrm{\Sigma }}_b^0$ and ${\mathrm{\Sigma }}_b^{*0}$. Our calculation shows that most of those missing $\lambda$-mode $P$-wave singly heavy baryons have a relatively narrow decay width of less than 30 MeV. Their dominant strong and radiative decay channels can be ideal for searching for their signals in future experiments. The ${\mathrm{\Sigma }}_c(2800)$ resonance may be assigned to $|{\mathrm{\Sigma }}_c{{}^{2}P}_{\lambda }{\frac{3}{2}}^{-}⟩$ with $J^P=3/2^{-}$ or $|{\mathrm{\Sigma }}_c{{}^{4}P}_{\lambda }{\frac{5}{2}}^{-}⟩$ with $J^P=5/2^{-}$. In general, the excitations of $|{{}^{2}P}_{\lambda }{\frac{3}{2}}^{-}⟩$ and $|{{}^{4}P}_{\lambda }{\frac{5}{2}}^{-}⟩$ of the ${\mathbf{6}}_F$ multiplet have similar strong decay properties. In order to identify them, angular distributions of their decays in either strong decay modes or radiative transitions should be needed.

• Received 20 September 2017

DOI:https://doi.org/10.1103/PhysRevD.96.116016