Exotic hadrons and SU(3) chiral dynamics

TL;DR

This paper investigates the potential for dynamically generating exotic hadrons through hadron scattering, emphasizing the role of chiral interactions and their limitations in forming bound states.

Contribution

It develops a unitarized chiral scattering amplitude framework to analyze exotic hadron formation, revealing the generally repulsive nature of exotic channels.

Findings

Exotic channels are mostly repulsive, preventing bound state formation.

Attractive interactions in exotic channels are too weak to produce bound states.

Nonexotic channels can generate bound states, explaining some observed resonances.

Abstract

We explore a possibility to generate exotic hadrons dynamically in the scattering of hadrons. The s-wave scattering amplitude of an arbitrary hadron with the Nambu-Goldstone boson is constructed so as to satisfy the unitarity condition and the chiral low energy theorem. We find that the chiral interaction for the exotic channels is in most cases repulsive, and that the strength of the possible attractive interaction is uniquely determined. We show that the attractive interaction in exotic channels is not strong enough to generate a bound state, while the interaction in nonexotic channel generate bound states which are considered to be the origin of some resonances observed in nature.