Compositeness Of Quasibound States from Effective Field Theory

TL;DR

This paper extends Weinberg's weak-binding relation within effective field theory to better understand the internal structure of near-threshold exotic hadrons, providing a systematic way to estimate uncertainties and applying it to Lambda(1405).

Contribution

It develops an extended weak-binding relation for quasibound states and introduces a systematic error estimation method within effective field theory.

Findings

Lambda(1405) is predominantly composed of Kbar N.

Extended relation improves understanding of hadron structure.

Systematic uncertainty estimation enhances analysis reliability.

Abstract

The internal structure of exotic hadron candidates are studied from the viewpoint of the compositeness of near-threshold states. We focus on the Weinberg's weak-binding relation between the experimental observables and the compositeness of the state. First we extend the relation for quasibound states within the framework of the effective field theory. Next, considering the correction term, we develop a systematic method to estimate the uncertainty of compositeness in the weak-binding relation. Finally, applying the extended relation and the error evaluation method, we conclude that the structure of Lambda(1405) is dominated by the Kbar N component.