Pith. Sign in

REVIEW

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

High Energy Physics - Phenomenology · Submitted 6 Oct 2026 · 19 references

Pith's verdict: A plausible regime criterion announced in a companion letter whose quantitative support all lives in the same authors' unreviewed preprint; useful and clearly framed, but not established on its own.

T0 · AI review

How this review was made: An AI referee (deepseek/deepseek-v4-flash) read the paper on October 7, 2026 and answered a fixed list of questions about it. T0 is the starting level every paper gets. The levels describe how deeply Pith has checked the paper, never the authors.

  1. T0 AI review An AI read the paper and answered a fixed list of questions.
  2. T1 Audit Automatic checks that the references and files the paper relies on exist and match.
  3. T2 Compute The paper's code or calculations re-run with the same results.
  4. T3 Formal statement The claims written out in a formal math language a computer can read.
  5. T4 Proof Those claims proved, and the proof checked by computer.

How Pith checks papers →

· 3 major objections · 5 minor · Ask about this paper · The compiled record · Read the full review →
Challenge this review Comment (0) Read on arXiv ↗
Cite ▾
arXiv ID2610.08340 (version 1)
Pith IDZSLS6AJU, Pith's permanent record of this paper and its review
CitationTetsuo Hyodo, Tomona Kinugawa. "Compositeness of near-threshold exotic hadrons in systems with Coulomb and short-range interactions." arXiv:2610.08340 (2026). https://pith.science/paper/ZSLS6AJU
Cite this reviewBibTeX for Pith's review of this paper
Claim paper

Why Pith says this

Highlight any text to comment on it.

Referee report
The paper

The paper claims

A single ratio — Coulomb effective range over Bohr radius — decides whether near-threshold hadron states stay composite-dominant despite long-range Coulomb forces.

The reading

This paper asks whether the long-range Coulomb force erases the low-energy universality that makes near-threshold states in purely short-range systems composite-dominant. Its answer is that a single dimensionless ratio controls the outcome: the Coulomb effective range $r_C^e$ relative to the Bohr radius $a_B$. When $|r_C^e|/a_B \ll 1$ the Coulomb force is weak at the relevant scales, an intermediate momentum window opens where the short-range interaction alone governs the pole, and near-threshold bound states (and, for repulsive Coulomb, nearby resonances) stay composite-dominant. When $|r_C^e|/a_B \gg 1$ that window closes, the compositeness enhancement disappears, and near-threshold states need not be composite-dominant. If correct, the criterion gives a practical flag for when Coulomb effects must be folded into structure analyses of candidates like the X(3872) and T_cc.

What carries the argument

The argument runs through the Coulomb-distorted short-range scattering amplitude $f^{CS}(k)$ of Eq. (1), whose denominator contains the Coulomb scattering length $a_C^s$, the Coulomb effective range $r_C^e$, and the Coulomb term $-2 k_C H(\eta)$, together with the compositeness formula $X = [1 - r_C^e/R_C]^{-1}$, where $R_C$ is the wave-function length scale in the presence of Coulomb interaction. The load-bearing mechanism is the scale-separation window $1/a_B \ll k \ll 1/|r_C^e|$: when such a window exists, the pole is governed primarily by the scattering length and the short-range universality leaves a remnant that pushes $X$ toward unity.

Extended reading notes

Core claim

On the paper's own terms, the central claim is that the ratio $|r_C^e|/a_B$ of the Coulomb effective range to the Bohr radius determines whether a remnant of short-range low-energy universality survives in systems with Coulomb plus short-range interactions. In the weak-Coulomb regime $|r_C^e|/a_B \ll 1$, there is a momentum window $1/a_B \ll k \ll 1/|r_C^e|$ in which both the Coulomb term and the effective-range term in the Coulomb-distorted scattering amplitude are negligible, so the pole is set by the Coulomb scattering length; the compositeness of near-threshold bound states is then enhanced toward unity, and for repulsive Coulomb the bound state's composite-dominant nature persists into the resonance region across the threshold. In the strong-Coulomb regime $|r_C^e|/a_B \gg 1$, the Coulomb-dominant region is reached before the universal window can open, the enhancement disappears, and near-threshold states are not necessarily composite-dominant.

Load-bearing premise

The load-bearing premise is that a genuinely empty intermediate momentum window $1/a_B \ll k \ll 1/|r_C^e|$ exists in which the Coulomb form factor $-2 k_C H(\eta)$ is negligible; the paper infers this from the Bohr-radius scale but does not analyze $H(\eta)$ or verify that the Coulomb-modified effective-range expansion remains accurate there.

Editorial extensions

If this is right

  • The ratio $|r_C^e|/a_B$ becomes a quantitative screening criterion: candidates with $|r_C^e|/a_B \ll 1$ can be treated under short-range universality, while those with the ratio of order one or larger require Coulomb-corrected structure analyses.
  • For repulsive Coulomb systems in the weak-Coulomb regime, near-threshold resonances inherit the composite-dominant nature of the connected bound state across the threshold, extending the universal expectation into the resonance region.
  • For attractive Coulomb systems, the compositeness approaches unity at the pure Coulomb ground state regardless of the effective range, and does so faster in the weak-Coulomb regime.
  • Systems of the 8Be type, where switching off Coulomb repulsion turns a near-threshold resonance into a bound state, illustrate the qualitative sensitivity of the pole structure to the long-range force that this scheme aims to characterize.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The criterion could serve as a red flag in experimental searches: a narrow near-threshold candidate with $|r_C^e|/a_B$ of order one or larger should not be assumed composite-dominant without explicitly accounting for Coulomb distortions.
  • The composite-dominant conclusion for repulsive-Coulomb resonances depends on the specific interpretation prescription applied to the complex compositeness; a different prescription could shift that reading.
  • The same scale-separation logic may extend to other long-range power-law forces, such as dipole or van der Waals interactions, with an analogous dimensionless ratio controlling the surviving remnant of universality.
Original 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.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-10-07: 1 request, 4,326 input tokens.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.22 · human participants 0.01 · controlled comparison 0.25 · randomized assignment 0.01 · states quantitative result 0.07 · compares with prior results 0.58 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

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.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We study the universal properties of near-threshold $s$-wave eigenstates in systems with Coulomb plus short-range interactions by analyzing their compositeness. contribution 0.99 0.94 0.07 asserted 0.81
s1 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. method 0.66 0.96 0.13 asserted 1.00
s2 We find that the long-range Coulomb interaction modifies the threshold behavior expected from the low-energy universality of purely short-range systems. result 0.97 0.94 0.31 asserted 1.00
s3 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. result 0.88 0.89 0.35 asserted 0.99
s4 In contrast, in the strong-Coulomb regime, this remnant disappears. result 0.98 0.86 0.16 asserted 1.00

What kind of paper the classifier reports this is: theoretical result 1.00 · evidence from proof or derivation 1.00.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

References

Discussion

Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.