Coulomb Effects in Momentum-Space Femtoscopy: A Case Study of the $\bar{K}\Omega$ System

Albert Feijoo; Amador Garc\'ia-Lorenzo; Isaac Vida\~na; Juan Nieves; Miguel Albaladejo; Pablo Encarnaci\'on

REVIEW

Coulomb Effects in Momentum-Space Femtoscopy: A Case Study of the $\bar{K}\Omega$ System

Pablo Encarnación, Amador García-Lorenzo, Miguel Albaladejo, Albert Feijoo, Juan Nieves, Isaac Vidaña

High Energy Physics - Phenomenology · Submitted 13 Jul 2026

Pith's verdict: Abstract-only methods paper on a modified Vincent-Phatak Coulomb treatment for momentum-space femtoscopy; useful scoped contribution, but the free phenomenological parameter is the real soft spot and cannot be checked without the full text.

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arXiv ID2607.11321 (version 2)

Pith IDK3C6YTXG, Pith's permanent record of this paper and its review

CitationAlbert Feijoo, Amador Garc\'ia-Lorenzo, Isaac Vida\~na, Juan Nieves, Miguel Albaladejo, Pablo Encarnaci\'on. "Coulomb Effects in Momentum-Space Femtoscopy: A Case Study of the $\bar{K}\Omega$ System." arXiv:2607.11321 (2026). https://pith.science/paper/K3C6YTXG

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Editor's note

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This is an abstract-only read, so everything below is provisional. The punchline is a practical, modified Vincent-Phatak scheme that puts Coulomb inside the Lippmann-Schwinger equation for femtoscopic correlation functions in momentum space, applied to the charged K-bar Omega channels and checked on pp, plus an explicit look at short-distance corrections beyond the asymptotic wave-function approximation.

What looks new and useful is the numerical packaging: they claim a version of Vincent-Phatak that is easier to implement while still treating strong and Coulomb on the same footing at the short distances that matter for femtoscopy. Applying it to S=-4 K-bar Omega (singly and doubly charged) and validating on the well-studied pp system is a sensible choice of targets. Quantifying the short-distance corrections to the asymptotic approximation is also the right thing to do; that is real methodological hygiene rather than window dressing.

The soft spot is exactly the one the authors flag themselves: a single phenomenological parameter that “effectively absorbs” finite source size and off-shell structure. Those are the ingredients that shape the correlation function, so there is a genuine risk that the parameter reabsorbs the short-distance strong dynamics femtoscopy is supposed to constrain. Without equations, figures, or the concrete fitting procedure we cannot tell how tightly that parameter is controlled or whether the pp validation actually probes the same regime relevant to K-bar Omega. That is a load-bearing limitation of the abstract, not a manufactured flaw. Circularity burden is real but not fatal if the paper later shows the parameter is fixed independently or varied systematically.

Who it is for: people who actually compute femtoscopic correlation functions for charged multi-strange pairs and need a cleaner momentum-space Coulomb treatment. Not a field-reorganizing result; scoped impact inside heavy-ion and hadron physics. It deserves a serious referee who can inspect the modified Vincent-Phatak construction, the short-distance correction numbers, and how the free parameter is handled. I would send it to peer review rather than desk-reject; the abstract is coherent and the problem is real. I would not cite it yet and would only bring it to reading group if someone is actively working on charged femtoscopy.

Referee report

Major objections (4)

Abstract (and stated main remaining obstacle): the single phenomenological parameter is defined to absorb both finite source size and the off-shell structure of the interaction—precisely the ingredients that shape the correlation function. Without an explicit definition, fitting protocol, and demonstration that the short-distance strong dynamics remain identifiable after this absorption (e.g., via controlled variations or residual sensitivity plots), it is unclear that the parameter does not reabsorb the information femtoscopy is meant to constrain. This is load-bearing for the central claim of enabling useful strong-plus-Coulomb predictions.
Abstract (modified Vincent–Phatak construction): the claim of a practical, consistent Coulomb treatment inside the Lippmann–Schwinger equation rests on the modification of the Vincent–Phatak method. With only the abstract available, the concrete modification, matching conditions, numerical stability at the short distances relevant for femtoscopy, and the size of any residual cutoff or discretization artifacts cannot be checked. These details are load-bearing for the formalism’s reliability.
Abstract (pp validation vs. K̄Ω application): validation on pp is valuable, but pp and K̄Ω probe different reduced masses, charge products, and short-distance strong dynamics. The manuscript must show that the same short-distance regime and the same phenomenological absorber are constrained by the pp exercise in a way that transfers to the charged K̄Ω channels; otherwise the validation does not underwrite the K̄Ω predictions.
Abstract (short-distance corrections to the asymptotic wave-function approximation): the paper states that it quantifies corrections from the short-distance structure of the potential. The magnitude and channel dependence of those corrections relative to the claimed precision of the K̄Ω predictions are load-bearing; if they are large, the asymptotic approximation’s limitations must be reflected in the uncertainty of the reported correlation functions.

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The paper

The paper claims

A modified Vincent-Phatak method puts Coulomb into momentum-space femtoscopy for charged K-bar Omega pairs.

The reading

The paper aims to give femtoscopy a practical, consistent way to include Coulomb forces inside the same momentum-space Lippmann-Schwinger equation that already carries the strong interaction. It does so with a modified Vincent-Phatak method that is easier to implement numerically, so short-distance Coulomb and strong dynamics can be treated together rather than stitched on afterwards. As a concrete application it computes correlation functions for the singly and doubly charged K-bar Omega channels in the S=-4 sector, and it checks the machinery on the well-known pp system. The work also measures how much the usual asymptotic wave-function approximation misses once the short-distance structure of the potential is kept, and it introduces one phenomenological parameter that absorbs both finite source-size effects and off-shell contributions. A sympathetic reader cares because femtoscopy is one of the few experimental windows on exotic hadron-hadron forces, yet Coulomb contamination and off-shell ambiguities have limited how cleanly those forces can be read out; a unified treatment plus a controlled handle on the remaining uncertainty would make the extraction more trustworthy.

What carries the argument

The modified Vincent-Phatak method: a momentum-space reformulation of Coulomb-plus-strong scattering that is more amenable to numerical solution of the Lippmann-Schwinger equation at the short distances that dominate femtoscopic correlation functions.

Extended reading notes

Core claim

A modified Vincent-Phatak method supplies a practical, numerically tractable way to embed Coulomb effects inside the Lippmann-Schwinger equation for femtoscopic correlation functions, yielding unified strong-plus-Coulomb predictions for the charged K-bar Omega channels that are validated on the pp system and that quantify the shortfalls of the asymptotic wave-function approximation.

Load-bearing premise

That one phenomenological parameter can absorb both finite source-size effects and the off-shell structure of the interaction without erasing the short-distance strong dynamics that femtoscopy is meant to constrain.

Original abstract

We present a momentum-space framework for the consistent treatment of Coulomb interactions in femtoscopic correlation functions based on a modified Vincent--Phatak method that is more amenable to numerical implementation. The formalism provides a practical approach to incorporating Coulomb effects at the short distances relevant for femtoscopy within the Lippmann--Schwinger equation, while preserving a unified treatment of the strong interaction. As an application, we study the $S=-4$ pseudoscalar--baryon decuplet interaction in the $\bar{K}\Omega$ system and present predictions for the singly and doubly negatively charged channels, $\bar{K}^0\Omega^-$ and $K^-\Omega^-$. As an additional validation of the formalism, we have also applied it to the well-studied $pp$ system. We further assess the limitations of the asymptotic wave-function approximation and quantify corrections accounting for the short-distance structure of the interaction potential. We introduce a phenomenological parameter that effectively absorbs contributions from both the finite source size and the off-shell structure of the interaction, the latter being one of the main obstacles to extracting detailed information on hadron--hadron interactions from femtoscopic measurements in a model-independent way.

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, 2026-09-23: 1 request, 5,156 input tokens.

What the abstract itself states, as probabilities: claims first 0.05 · states limitation 0.88 · human participants 0.01 · controlled comparison 0.08 · randomized assignment 0.01 · states quantitative result 0.06 · compares with prior results 0.49 · mentions code or data availability 0.02.

The abstract, sentence by sentence

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

We present a momentum-space framework for the consistent treatment of Coulomb interactions in femtoscopic correlation functions based on a modified Vincent--Phatak method that is more amenable to numerical implementation. The formalism provides a practical approach to incorporating Coulomb effects at the short distances relevant for femtoscopy within the Lippmann--Schwinger equation, while preserving a unified treatment of the strong interaction. As an application, we study the $S=-4$ pseudoscalar--baryon decuplet interaction in the $\bar{K}\Omega$ system and present predictions for the singly and doubly negatively charged channels, $\bar{K}^0\Omega^-$ and $K^-\Omega^-$. As an additional validation of the formalism, we have also applied it to the well-studied $pp$ system. We further assess the limitations of the asymptotic wave-function approximation and quantify corrections accounting for the short-distance structure of the interaction potential. We introduce a phenomenological parameter that effectively absorbs contributions from both the finite source size and the off-shell structure of the interaction, the latter being one of the main obstacles to extracting detailed information on hadron--hadron interactions from femtoscopic measurements in a model-independent way.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	We present a momentum-space framework for the consistent treatment of Coulomb interactions in femtoscopic correlation functions based on a modified Vincent--Phatak method that is more amenable to numerical implementation.	contribution 0.52	0.95	0.17	asserted 1.00
s1	The formalism provides a practical approach to incorporating Coulomb effects at the short distances relevant for femtoscopy within the Lippmann--Schwinger equation, while preserving a unified treatment of the strong interaction.	method 0.84	0.81	0.11	asserted 1.00
s2	As an application, we study the $S=-4$ pseudoscalar--baryon decuplet interaction in the $\bar{K}\Omega$ system and present predictions for the singly and doubly negatively charged channels, $\bar{K}^0\Omega^-$ and $K^-\Omega^-$.	contribution 0.99	0.95	0.13	asserted 1.00
s3	As an additional validation of the formalism, we have also applied it to the well-studied $pp$ system.	contribution 0.77	0.95	0.03	asserted 0.99
s4	We further assess the limitations of the asymptotic wave-function approximation and quantify corrections accounting for the short-distance structure of the interaction potential.	contribution 0.78	0.94	0.08	asserted 1.00
s5	We introduce a phenomenological parameter that effectively absorbs contributions from both the finite source size and the off-shell structure of the interaction, the latter being one of the main obstacles to extracting detailed information on hadron--hadron interactions from femtoscopic measurements in a model-independent way.	contribution 0.74	0.92	0.31	asserted 1.00

What kind of paper the classifier reports this is: method or tool 1.00 · evidence from simulation or computation 0.57.

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

Forward citations

Cited by 3 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

A femtoscopic tale of two $C$-parities: the $Z_c(3900)$ and the isovector partner of the $X(3872)$
hep-ph 2026-08 conditional novelty 7.0 of 10

Femtoscopic correlations of charged charm meson pairs mix C-odd and C-even interactions, giving a new experimental probe of the predicted W_c1 state and correcting earlier predictions.
The $D\pi$ and $D^*\pi$ femtoscopy puzzle
hep-ph 2026-09 conditional novelty 6.0 of 10

The theoretical Dπ and D*π correlation functions disagree with ALICE, and the paper traces the gap to the experiment's assumption that genuine correlations vanish above 100 MeV relative momentum.
A coupled-channel quark model study of possible $\Xi_{cc}^{(*)} K^{(*)}$ molecular states
hep-ph 2026-07 conditional novelty 6.0 of 10

A quark-model calculation predicts a Ξ_ccK bound state plus four other Ξ_cc^(*)K^(*) molecular candidates with definite spin-parity and narrow widths.

How the literature uses it

2 arXiv papers cite this in 3 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

What it cites · 74 sentences without a confident label

Uses the method or tool of 3 papers

The relative wave function appearing in Eq. ([ref]), $ψ^0(k,r)$, can be obtained from the half-off-shell scattering amplitude $T(k,q)$ (transition amplitude from an off-shell hadron-pair with momentum $q$ to the on-shell one with momentum $k$) by solving the LSE [ref]

Femtoscopic correlation function for the $T_{cc}(3875)^+$ state · Exact wave function · 0.82
The relative wave function appearing in Eq. ([ref]), $ψ^0(k,r)$, can be obtained from the half-off-shell scattering amplitude $T(k,q)$ (transition amplitude from an off-shell hadron-pair with momentum $q$ to the on-shell one with momentum $k$) by solving the LSE [ref]

2503.18710 · Exact wave function · 0.82
As a benchmark for our treatment of the Coulomb interaction, we first solve the Schrödinger equation in coordinate space using the Numerov method [ref] with the Argonne V18 nucleon–nucleon potential [ref] , treating the Coulomb interaction, $V_C(r)=α/r$, exactly.

An accurate nucleon-nucleon potential with charge-independence breaking · Regularized Coulomb interaction · 0.97

Compares with 2 papers

This value reproduces the same scattering length as the sharp cutoff $Λ= 814$ MeV used in Ref. [ref] to generate the $Ω(2012)^-$ in the $S=-3$ sector, employing the same strong Lagrangian as in the present work.

Signatures of the $\Omega(2012)^{-}$ state in $\Xi^*\bar K$ Correlation Functions · Strong potential · 0.81
The phase shifts reported in the original paper of Ref. [ref] are also shown for comparison.

An accurate nucleon-nucleon potential with charge-independence breaking · Regularized Coulomb interaction · 1.00

Cites as support 2 papers

In practice, in the analysis of measured CFs, a simultaneous fit of the phenomenological $β$ parameter together with the on-shell amplitude may provide an effective way to account for off-shell ambiguities in femtoscopic CFs.[Reference [ref] proposes a simultaneous fit of the on-shell amplitude and the source radius.] In this regard, the results shown in Figs. 2–4 of Ref. [ref] support this strategy.

2503.18710 · Results · 0.99
In practice, in the analysis of measured CFs, a simultaneous fit of the phenomenological $β$ parameter together with the on-shell amplitude may provide an effective way to account for off-shell ambiguities in femtoscopic CFs.[Reference [ref] proposes a simultaneous fit of the on-shell amplitude and the source radius.] In this regard, the results shown in Figs. 2–4 of Ref. [ref] support this strategy.

Off-shell ambiguities in correlation functions: strategies to minimize them · Results · 0.99

Cites as background 1 paper

Within the framework of unitarized effective field theories (UEFTs), an early study addressed this problem by deriving the leading $S$-wave interaction of Goldstone bosons with baryon-decuplet states using a chiral coupled-channel approach driven by the Weinberg–Tomozawa (WT) term [ref] .

On baryon resonances and chiral symmetry · Introduction · 0.95

Discussion

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