# Very narrow excited $\Omega_c$ baryons

## TL;DR

This paper interprets five narrow excited $ ext{Ω}_c$ baryons as $c$-quark and $ss$-diquark bound states with specific spin and orbital configurations, predicting their properties and decay modes based on quark model relations.

## Contribution

It provides a detailed quark model interpretation of the five narrow $ ext{Ω}_c$ states, including their spin, parity, and decay characteristics, and compares these with experimental data.

## Key findings

- Five possible spin and parity configurations for the states.
- Predicted decay modes include $S$-wave and $D$-wave decays.
- Mass relations and spin assignments are consistent with observed data.

## Abstract

Recently LHCb reported the discovery of five extremely narrow excited $\Omega_c$ baryons decaying into $\Xi_c^+ K^-$. 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 relations among the five masses expected in the quark model and the likely spin assignments and compare with the data. A similar pattern is expected for negative-parity excited $\Omega_b$ states. An alternative interpretation is noted in which the heaviest two states are $2S$ excitations with $J^P = 1/2^+$ and $3/2^+$, while the lightest three are those with $J^P = 3/2^-,3/2^-,5/2^-$ expected to decay via $D$-waves. In this case we expect $J^P = 1/2^-$ $\Omega_c$ states around 2904 and 2978 MeV.