Compositeness of near-threshold states in charged hadronic systems

TL;DR

This paper develops a method to quantify the internal structure of near-threshold states in systems with Coulomb and short-range interactions, applying it to various hadronic and nuclear states.

Contribution

It introduces a Coulomb-modified effective range expansion to evaluate compositeness of near-threshold states, extending previous models.

Findings

Derived an expression for compositeness in the weak-binding limit.

Applied the formulation to multiple hadronic and nuclear systems.

Provided insights into the internal structure of near-threshold states.

Abstract

We quantify the internal structure of near-threshold bound, virtual, and resonance states in systems where Coulomb and short-range interactions coexist by evaluating the compositeness. Using the Coulomb-modified effective range expansion, we derive an expression for the compositeness in terms of the eigenenergy and Coulomb effective range in the weak-binding limit. We then apply the formulation to several near-threshold states in hadronic and nuclear systems, including $pp$, $\alpha\alpha$, $\Omega^{-}\Omega^{-}$, $\Omega_{ccc}^{++}\Omega_{ccc}^{++}$, $\Xi^{-}\alpha$, and $\Omega^{-}p$.