Heavy baryon decay widths in the large $N_c$ limit in chiral theory

TL;DR

This paper investigates heavy baryon decay widths in the large N_c limit within chiral theory, revealing that all decay widths vanish as N_c approaches infinity, and explores decay coupling hierarchies explaining experimental patterns.

Contribution

It introduces large N_c generalizations for heavy baryon representations and demonstrates that decay widths vanish in the large N_c limit based on symmetry considerations.

Findings

All decay widths vanish as N_c approaches infinity.

Hierarchy of decay couplings explains experimental width patterns.

Decay constants derived in the non-relativistic limit support the hierarchy.

Abstract

We propose large $N_c$ generalizations for the "diquark" representations of SU(3)$_{\rm flav}$ relevant for positive parity heavy baryons, including putative exotic states. Next, within the framework of the Chiral Quark Soliton Model, we calculate heavy baryon masses and decay widths. We show that in the limit of $N_c \rightarrow \infty$ {\em all} decay widths vanish, including the widths of exotica. This result is in fact more general than the model itself, as it relies only on the underlying symmetries: i.e. SU(3)$_{\rm flav}$ and hedgehog symmetry. Furthermore, using explicit model formulae for the decay constants in the non-realtivistic limit, we show that there is a hierarchy of the decay couplings, which may explain observed pattern of experimental widths.