Compositeness of near-threshold exotic hadrons in systems with Coulomb and short-range interactions

Tomona Kinugawa; Tetsuo Hyodo

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arXiv · 2610.08340

Compositeness of near-threshold exotic hadrons in systems with Coulomb and short-range interactions

Tomona Kinugawa·Tetsuo Hyodo

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Abstract

We study the universal properties of near-threshold $s$-wave eigenstates in systems with Coulomb plus short-range interactions by analyzing their compositeness. Using a nonrelativistic effective field theory, we derive a relation between the compositeness of near-threshold states and the Coulomb scattering length, the Coulomb effective range, and the Bohr radius. We find that the long-range Coulomb interaction modifies the threshold behavior expected from the low-energy universality of purely short-range systems. When the Coulomb interaction is relatively weak compared with the short-range interaction, a remnant of the low-energy universality associated with the short-range interaction survives, leading to composite-dominant near-threshold eigenstates. In contrast, in the strong-Coulomb regime, this remnant disappears.

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Tomona Kinugawa, Tetsuo Hyodo. 2026-10-06. Compositeness of near-threshold exotic hadrons in systems with Coulomb and short-range interactions. https://arxiv.org/abs/2610.08340

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