In this work, we systematically investigate the singly-charmed pentaquark molecular states $D^{ (*)}N$, $D^{ (*)}\Xi^{ (*)}$ and $D_s^{ (*)}\Xi^{ (*)}$ with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 13 and taking fully account of the light-flavor $SU(3)$ breaking effects. The numerical results favor assigning the $\Omega_c(3185)$ as the $D\Xi$ molecular state with the $J^P=\frac{ 1}{ 2}^-$ and $| I,I_3 \rangle=| 0,0 \rangle$, assigning the $\Omega_c(3327)$ as the $D^*\Xi$ molecular state with the $J^P=\frac{ 3}{ 2}^-$ and $|I,I_3 \rangle=| 0,0 \rangle$, assigning the $\Sigma_c(2800)$ as the $DN$ molecular state with the $J^P=\frac{ 1}{ 2}^-$ and $| I,I_3 \rangle=| 1,0 \rangle$, and assigning the $\Lambda_c(2940)/\Lambda_c(2910)$ as the $D^*N$ molecular state with the $J^P=\frac{ 3}{ 2}^-$ and $| I,I_3 \rangle=| 0,0 \rangle$. Other potential molecule candidates are also predicted, which may be observed in future experiments. For example, we can search for the $D\Xi$ and $D^*\Xi$ molecular states with the isospin $| I,I_3 \rangle=| 1,\pm1 \,\rangle$ in the $\Xi_c^+\bar{ K}^0$ and $\Xi_c^0\bar{ K}^-$ mass spectrum respectively in the future, which could shed light on the nature of the $\Omega_c(3185/3327)$.
Categories: hep-ph