Threshold Cusp Structures in the Presence of Isospin Symmetry Breaking

TL;DR

This paper investigates how isospin symmetry breaking affects cusp structures near thresholds in hadron scattering, providing a practical framework to analyze the relationship between neighboring cusp features.

Contribution

It introduces a new representation of the scattering amplitude that relates cusp structures at closely spaced thresholds under isospin symmetry breaking.

Findings

Cusp structures are sensitive to isospin-breaking effects.

The proposed model links neighboring cusp structures through isospin symmetry.

Near-threshold exotic hadron properties are encoded in cusp shapes.

Abstract

We study the behavior of the cusp structures focusing on the isospin-breaking effects. The properties of the near-threshold exotic hadrons are encoded in the shapes of the cusp structures. In hadron scattering, it is often the case that the thresholds of isospin partner channels are located within a narrow energy region. To analyze the scattering in such systems, it is therefore essential to study the cusp structures that emerge at two closely separated thresholds with isospin symmetry breaking. In this study, we propose a practical representation of the scattering amplitude and show that the two neighboring cusp structures are related through the isospin symmetry.