Excited baryon decay widths in large $N_c$ QCD

We study excited baryon decay widths in large $N_c$ QCD. It was suggested previously that some spin-flavor mixed-symmetric baryon states have strong couplings of ${O(N}_c^{-1/2})$ to nucleons [implying narrow widths of ${O(1/N}_c\left)\right],$ as opposed to the generic expectation based on Witten’s counting rules of an ${O(N}_c^0)$ coupling. The calculation obtaining these narrow widths was performed in the context of a simple quark-shell model. This paper addresses the question of whether the existence of such narrow states is a general property of large $N_c$ QCD. We show that a general large $N_c$ QCD analysis does not predict such narrow states; rather they are a consequence of the extreme simplicity of the quark model.