Excited $\Omega_b$ baryons and fine structure of strong interaction

The heavy baryon system bounded by the strong interaction has a rich internal structure, so its mass spectra can have the fine structure similar to the line spectra of atom bounded by the electromagnetic interaction. We systematically study the internal structure of $P$-wave $\Omega_b$ baryons and calculate their $D$-wave decay properties. The present study, together with our previous studies on their mass spectra and $S$-wave decay properties, suggest that all the four excited $\Omega_b$ baryons recently discovered by LHCb can be well explained as $P$-wave $\Omega_b$ baryons, and their beautiful fine structure is directly related to the rich internal structure of $P$-wave $\Omega_b$ baryons.