Compositeness of near-threshold states in charged hadronic systems

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 ${\Omega }^{-}p$.

Comments: 4 pages, Proceedings of the 2025 International Conference on the Structure of Baryons (Baryons 2025), November 10th - 14th, 2025