We have systematically studied the strong and radiative decays of the low-lying $1P$-wave doubly charmed baryons. Some interesting observations are: (i) The states ${\mathrm{\Xi }}_{cc}^{*}$ and ${\mathrm{\Omega }}_{cc}^{*}$ with $J^P=3/2^{+}$ have a fairly large decay rate into the ${\mathrm{\Xi }}_{cc}\gamma$ and ${\mathrm{\Omega }}_{cc}\gamma$ channels with a width $\sim 15$ and $\sim 7\mathrm{keV}$, respectively. (ii) The lowest lying excited doubly charmed baryons are dominated by the $1P$ $\rho$ mode excitations, which should be quite narrow states. They decay into the ground state with $J^P=1/2^{+}$ through the radiative transitions with a significant ratio. (iii) The total decay widths of the first orbital excitations of $\lambda$ mode ($1P_{\lambda }$ states with $J^P=1/2^{-}$, $3/2^{-}$, $5/2^{-}$) are about $\mathrm{\Gamma }\sim 100\mathrm{MeV}$, and the ratio between the radiative and hadronic decay widths is about $\mathcal{O}({10}^{-3})$.

The $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ observed by the LHCb collaboration are very likely to be $S$-wave ${\mathrm{\Sigma }}_c{\overline{D}}^{(*)}$ molecular candidates due to their near threshold character. In this work, we study the hidden-charm decay modes of these $P_c$ states, $P_c\to J/\psi p({\eta }_{c}p)$, using a quark interchange model. The decay mechanism for the $P_c\to J/\psi p({\eta }_{c}p)$ processes arises from the quark-quark interactions, where all parameters are determined by the mass spectra of mesons. We present our results in two scenarios. In scenario I, we perform the dynamical calculations and treat the $P_c$ states as pure ${\mathrm{\Sigma }}_c{\overline{D}}^{(*)}$ molecules. In scenario II, after considering the coupled channel effect between different flavor configurations ${\mathrm{\Sigma }}_c^{(*)}{\overline{D}}^{(*)}$, we calculate these partial decay widths again. The decay patterns in these two scenarios can help us to explore the molecular assignment and the inner flavor configurations for the $P_c$ states. In particular, the decay widths of $\mathrm{\Gamma }(P_c(4312)\to {\eta }_{c}p)$ are comparable to the $J/\psi p$ decay widths in both of these two scenarios. Future experiments like LHCb may confirm the existence of the $P_c(4312)$ in the ${\eta }_{c}p$ channel.

We systematically study the mass spectrum and strong decays of the S-wave $${\bar{c}}{\bar{s}} q q$$c ¯ s ¯ q q states in the compact tetraquark scenario with the quark model. The key ingredients of the model are the Coulomb, the linear confinement, and the hyperfine interactions. The hyperfine potential leads to the mixing between different color configurations, and to the large mass splitting between the two ground states with $$I(J^P)=0(0^+)$$I ( J P ) = 0 ( 0 + ) and $$I(J^P)=1(0^+)$$I ( J P ) = 1 ( 0 + ) . We calculate their strong decay amplitudes into the $${\bar{D}}^{(*)}K^{(*)}$$D ¯ ( ∗ ) K ( ∗ ) channels with the wave functions from the mass spectrum calculation and the quark-interchange method. We examine the interpretation of the recently observed $$X_0(2900)$$X 0 ( 2900 ) as a tetraquark state. The mass and decay width of the $$I(J^P)=1(0^+)$$I ( J P ) = 1 ( 0 + ) state are $$M=2941$$M = 2941 MeV and $$\Gamma _X=26.6$$Γ X = 26.6 MeV, respectively, which indicates that it might be a good candidate for $$X_0(2900)$$X 0 ( 2900 ) . Meanwhile, we also obtain an isospin partner state $$I(J^P)=0(0^+)$$I ( J P ) = 0 ( 0 + ) with $$M=2649$$M = 2649 MeV and $$\Gamma _{X\rightarrow {\bar{D}} K}=48.1$$Γ X → D ¯ K = 48.1 MeV, respectively. Future experimental search for X(2649) will be very helpful.

We perform a systematical investigation of the strong decay properties of the low-lying $1P$- and $2D$-wave doubly charmed baryons with the ${}^3{P}_0$ quark pair creation model. The main predictions include: (i) in the ${\mathrm{\Xi }}_{cc}$ and ${\mathrm{\Omega }}_{cc}$ family, the $1P$ $\rho$ mode excitations with $J^P=1/2^{-}$ and $3/2^{-}$ should be the fairly narrow states, while, for the $1P$ $\lambda$ mode excitations, they are most likely to be moderate states with a width of $\mathrm{\Gamma }\sim 100\mathrm{MeV}$. (ii) The $2D_{\rho \rho }$ states mainly decay via emitting a heavy-light meson and the decay widths can reach several tens MeV if their masses are above the threshold of ${\mathrm{\Lambda }}_{c}D$ or ${\mathrm{\Xi }}_{c}D$, respectively. The $2D_{\lambda \lambda }$ states may be broad states with a width of $\mathrm{\Gamma }>100\mathrm{MeV}$.

Inspired by the newly observed $\mathrm{\Omega }(2012)$ state at Belle II, we investigate the two-body strong decays of $\mathrm{\Omega }$ baryons up to $N=2$ shell within the chiral quark model. Our results indicate that (i) the newly observed $\mathrm{\Omega }(2012)$ state could be assigned to the spin-parity $J^P=3/2^{-}$ state $|{70,}^{2}10,1,1,{\frac{3}{2}}^{-}⟩$ and the experimental data can be reasonably described. However, the spin-parity $J^P=1/2^{-}$ state $|{70,}^{2}10,1,1,{\frac{1}{2}}^{-}⟩$ and spin-parity $J^P=3/2^{+}$ state $|{56,}^{4}10,2,0,{\frac{3}{2}}^{+}⟩$ cannot be completely excluded. (ii) The $D$-wave states in the $N=2$ shell are most likely to be narrow states with a width of dozens of MeV and have a good potential to be observed in the $\mathrm{\Xi }K$ and/or $\mathrm{\Xi }(1530)K$ channels in future experiments. The $\mathrm{\Omega }(2250)$ resonance listed in PDG may be a good candidate for the $J^P=5/2^{+}$ $1D$ wave state $|{56,}^{4}10,2,2,5/2^{+}⟩$.

Considering the mass, parity and [equation] decay mode, we tentatively assign the [equation] as the [equation]wave states with one radial excitation. Then, via studying the strong decay behavior of...