Very narrow excited Ωc baryons

Recently, LHCb reported the discovery of five extremely narrow excited Ωc baryons decaying into Ξc+K-. We interpret these baryons as bound states of a c quark and a P-wave ss diquark. For such a system, there are exactly five possible combinations of spin and orbital angular momentum. The narrowness of the states could be a signal that it is hard to pull apart the two s quarks in a diquark. We predict two of spin 1/2, two of spin 3/2, and one of spin 5/2, all with negative parity. Of the five states, two can decay in S-wave, and three can decay in D-wave. Some of the D-wave states might be narrower than the S-wave states. We discuss the relations among the five masses expected in the quark model and the likely spin assignments, and we compare them with the data. A similar pattern is expected for negative-parity excited Ωb states. An alternative interpretation is noted in which the heaviest two states are 2S excitations with JP=1/2+ and 3/2+, while the lightest three are those with JP=3/2-, 3/2-, 5/2-, expected to decay via D-waves. In this case, we expect JP=1/2- Ωc states around 2904 and 2978 MeV.