Model-independent determination of the compositeness of near-threshold quasibound states

TL;DR

This paper extends a theoretical relation to analyze the internal structure of near-threshold exotic hadrons, concluding that the CDD pole contribution to Lambda(1405) is negligible, aiding understanding of its compositeness.

Contribution

The authors develop an extended weak-binding relation incorporating CDD poles using Pade approximants, providing a model-independent way to assess hadron compositeness.

Findings

The CDD pole contribution to Lambda(1405) is negligible.

Extended relation clarifies the internal structure of near-threshold states.

Framework can be applied to other exotic hadron candidates.

Abstract

We study the compositeness of near-threshold states to clarify the internal structure of exotic hadron candidates. Within the framework of effective field theory, we extend the Weinberg's weak-binding relation to include the nearby CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade approximant. Finally, using the extended relation, we conclude that the CDD pole contribution to the Lambda(1405) baryon in the Kbar N amplitude is negligible.