{"id":"d2899c9a-a39f-44a0-b82b-782c26aedbfa","arxiv_id":"2607.06255","paper_version":1,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":3,"one_line_summary":"The isospin-violating J/ψ→ΛΛ̄π⁰ decay is shown to selectively produce the dynamically-generated Σ(1430) resonance while suppressing the conventional Σ(1385) state, matching limited BESIII data.","lead":"This paper predicts that the isospin-violating decay J/ψ→ΛΛ̄π⁰ should show the dynamically-generated Σ(1430)(1/2⁻) resonance but NOT the conventional Σ(1385)(3/2⁺) three-quark state. It matters because it offers a clean experimental filter to distinguish 'molecular' baryons from 'quark-model' baryons using future high-statistics data from BESIII.","discovery_kind":"unclear","skeptic_critique":{"model":"glm-5.2","headline":"The 'filter' claim is circular: only dynamically-generated resonances appear because the framework excludes non-dynamically-generated ones by construction, making the absence of Σ(1385) a tautology rather than a prediction.","rationale":"The reader correctly identified that the dominance of the proposed rescattering mechanism is the weakest assumption, and that competing mechanisms could break the 'clean filter.' I agree with this assessment and the CONDITIONAL verdict. However, the reader framed the concern as 'if other mechanisms contribute, the filter breaks down.' My stress-test sharpens this: the filter claim is already circular as stated. The paper predicts the absence of Σ(1385) using a framework that structurally cannot produce it, then cites its absence as evidence that the reaction filters non-dynamically-generated states. This is a logical gap in the central claim, not merely an untested assumption about competing mechanisms. The experimental data (a single data point near 1430 MeV, no visible 1385 peak) is consistent with the calculation but cannot distinguish between 'the physics suppresses qqq states' and 'the model omits qqq states.' The theoretical framework itself (chiral unitary SU(3), rescattering topology) is internally consistent and well-established from prior work. The ratios Ā/B̃ = 1.44 and the loop functions are taken from external sources, which is appropriate. The concern is specifically about the interpretive claim — that the reaction is a 'filter' for dynamical generation — which overreaches what the calculation demonstrates. The calculation shows that the rescattering mechanism produces a Σ(1430)-like structure and does not produce a Σ(1385); it does not show that the reaction itself suppresses non-dynamically-generated states. This distinction matters because it affects how the future BESIII data should be interpreted: if a Σ(1385) peak appears with better statistics, the paper's framework would not necessarily be falsified — it would simply reveal that the framework is incomplete rather than serving as a universal filter. The verdict remains CONDITIONAL because the calculation is sound and the prediction (Σ(1430) visible, Σ(1385) absent in this specific topology) is testable, but the interpretive framing overstates what the mechanism demonstrates.","tokens_in":10626,"tokens_out":1067,"duration_ms":645977,"concrete_test":"Compute the amplitude for J/ψ→Λ̄Λπ⁰ using a model that includes a direct isospin-violating J/ψ→Λ̄Σ(1385) vertex (with the Σ(1385) parameterized as a Breit-Wigner with PDG mass/width) in addition to the rescattering diagrams of Fig. 1. If the resulting Λπ⁰ invariant mass distribution shows a visible Σ(1385) peak comparable to or exceeding the Σ(1430) structure, the claim that this reaction acts as a filter for dynamically-generated states is not supported by the dynamics — it is only supported by the specific choice of excluding direct qqq couplings.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The paper's central conceptual claim is that this reaction 'serves as an excellent instrument to probe the nature of low-lying Σ states' because 'only resonances that are dynamically generated by these interactions show up in the reaction.' This is presented as a physical filter: the Σ(1430) appears because it is dynamically generated, while the Σ(1385)(3/2+) does not because it is a conventional qqq state. However, this 'filter' is an artifact of the model's construction, not a derived physical property of the isospin-violating decay. The amplitudes in Eqs. (11)-(12) are built entirely from meson-baryon scattering amplitudes t_{MB,M'B'} taken from chiral unitary coupled-channel approaches (Refs. [4,32]). The Σ(1385)(3/2+) is a three-quark state with J^P = 3/2+; it does not appear as an S-wave pole in these meson-baryon scattering amplitudes. Therefore, the framework cannot produce it at tree level — not because the reaction physics suppresses it, but because the input scattering amplitudes do not contain it. The absence of the Σ(1385) is thus guaranteed by the model's inputs, making the 'prediction' of its absence circular. The paper does not demonstrate that a generic isospin-violating J/ψ→Λ̄Λπ⁰ amplitude must suppress qqq states; it only shows that *their specific rescattering topology*, which uses only meson-baryon unitarized amplitudes, naturally misses them. If the physical decay has any direct J/ψ→Λ̄Σ*(1385)→Λ̄Λπ⁰ coupling (an isospin-violating vertex not mediated by meson-baryon rescattering), this framework would not capture it, and the 'filter' interpretation would fail. The experimental comparison (Fig. 4, one data point above background) is too sparse to independently validate the mechanism.","agreement_with_reader":"partial"},"referee_report":{"model":"glm-5.2","summary":"The manuscript studies the isospin-violating decay J/ψ → Λ̄Λπ⁰ using an SU(3)-singlet construction of baryon–antibaryon–pseudoscalar meson states, followed by meson-baryon and meson-antibaryon rescattering amplitudes taken from chiral unitary coupled-channel approaches. The central claim is that this reaction acts as a 'filter' for dynamically generated resonances: the Σ(1430)(1/2⁻) appears because it is generated by meson-baryon interactions, while the conventional Σ(1385)(3/2⁺) does not because it is a three-quark state. The prediction is compared with limited-statistics BESIII data, where one data point near 1430 MeV is noted as suggestive.","tokens_in":10896,"tokens_out":3395,"duration_ms":162598,"significance":"The idea of using isospin-violating J/ψ decays as a selective probe of dynamically generated baryon states is interesting and potentially valuable for the hadron spectroscopy program. The formalism is built on established chiral unitary methods and prior work by the authors, and the prediction that Σ(1430) appears while Σ(1385) is absent is a genuine consequence of the chosen rescattering topology. The paper has essentially one free parameter (a global normalization), with the ratio Ã/B = 1.44 taken from prior work, which is a strength. The call for future high-statistics measurements at BESIII is well-motivated.","major_comments":[{"comment":"§I and §IV: The claim that this reaction 'serves as an excellent instrument to probe the nature of low-lying Σ states' because 'only resonances that are dynamically generated by these interactions show up' is not fully justified. The amplitudes in Eqs. (11)–(12) are constructed entirely from meson-baryon scattering amplitudes t_{MB,M'B'}, so the absence of the Σ(1385)(3/2⁺) is guaranteed by the model's inputs — it does not appear as an S-wave meson-baryon pole — rather than being derived as a consequence of the reaction's isospin-violating dynamics. The paper does not demonstrate that a generic isospin-violating J/ψ → Λ̄Λπ⁰ amplitude must suppress conventional qqq states. In particular, a direct isospin-violating J/ψ → Λ̄Σ*(1385) → Λ̄Λπ⁰ vertex (arising from quark mass differences in the decay Hamiltonian) is not discussed or bounded. The authors should qualify the 'filter' claim to make","section":null},{"comment":"§I, discussion of Ref. [21]: The competing triangle mechanism (J/ψ → Σ̄*Σ, followed by Σ̄* → Λ̄π and πΣ fusion) is mentioned but dismissed because the J/ψ → Σ̄*Σ branching ratios are unknown. However, this mechanism could produce the same Σ(1430) signal in the πΛ spectrum through a very different topology, and its potential contribution would undermine the uniqueness of the interpretation. The authors should at least estimate an upper bound on the triangle contribution or discuss whether the two mechanisms can be distinguished experimentally (e.g., via angular distributions or the Λ̄π⁰ vs. Λπ⁰ spectra).","section":null},{"comment":"§III, Fig. 4: The comparison with BESIII data is overstated. The 'signal' at 1430 MeV consists of a single data point above a smooth background that is itself taken from the experimental fit rather than derived from the theoretical framework. The statement that 'the data show a structure around M_{πΛ} = 1430 MeV that is reproduced by the theory' should be tempered to reflect that the data are consistent with the prediction but do not constitute evidence for it. The authors should also clarify the physical origin of the smooth background within their framework — is it from non-resonant rescattering, or is it purely phenomenological?","section":null}],"minor_comments":[{"comment":"§II, Eqs. (11)–(12): The notation eA and eB is introduced without explicit definition. Presumably e = Ã/B or a related combination, but this should be stated clearly.","section":null},{"comment":"§II, Eq. (17): The factor 2M₁₂·2M₂₃ in the numerator appears without explanation. A brief comment on its origin (phase space convention) would help the reader.","section":null},{"comment":"§II, below Eq. (10): The statement 'the terms with p_i in Eq. (10) will not contribute' for Type (a) diagrams should be cross-checked: the S-wave projection argument is standard but a one-sentence justification would improve clarity.","section":null},{"comment":"Fig. 4: The y-axis label and units are not clearly specified. The data points also lack visible error bars in the figure as described; if error bars are present, they should be made more visible.","section":null},{"comment":"References [19, 20, 25, 26, 29, 30, 31] are all dated 2026, suggesting these are very recent or concurrent preprints. The authors should ensure that any results borrowed from these works (particularly the ratio Ã/B = 1.44 from Refs. [26, 29]) are not themselves under revision.","section":null}],"recommendation":"major_revision","confidential_remarks":"The paper makes an interesting prediction but the 'filter' framing is conceptually circular as currently stated — the framework excludes qqq states by construction, so their absence is not a prediction of the reaction dynamics. This is fixable by qualifying the claim and discussing whether direct isospin-violating vertices could spoil the filter. The data comparison is too weak to support the strong claims made. I would encourage the authors to reframe the paper as a prediction awaiting experimental verification rather than a confirmation. The concurrent proliferation of closely related papers from the same group (Refs. [19, 20, 25, 26, 29, 30, 31]) suggests an active research program; the novelty of this specific application should be clearly distinguished from the prior work."},"author_rebuttal":{"model":"glm-5.2","summary":"We thank the referee for a careful and constructive report. The referee raises three major points: (1) the 'filter' claim is stronger than what the formalism demonstrates, since the absence of the Σ(1385) is built into the model inputs rather than derived from isospin-violating dynamics; (2) the competing triangle mechanism of Ref. [21] is dismissed without an upper bound or discussion of experimental discriminability; and (3) the comparison with BESIII data is overstated given that the 'signal' is a single data point and the background is phenomenological. We agree with the substance of all three points and will revise the manuscript accordingly.","responses":[{"response":"The referee is correct. The absence of the Σ(1385) in our amplitudes is a direct consequence of the fact that we build the decay from meson-baryon rescattering amplitudes taken from chiral unitary approaches, which produce S-wave meson-baryon poles but do not contain the Σ(1385)(3/2⁺) as a three-quark state. This is a feature of the model's construction, not a consequence derived from the isospin-violating dynamics themselves. We acknowledge that a direct isospin-violating vertex J/ψ → Λ̄Σ*(1385) → Λ̄Λπ⁰, arising from quark mass differences in the decay Hamiltonian, is in principle possible and is not discussed or bounded in the present work. We will revise the manuscript to qualify the 'filter' claim accordingly. Specifically, we will rephrase the claim to state that within the rescattering mechanism considered here, only dynamically generated resonances appear, and we will explicitly note that a direct production vertex for conventional qqq states is not included in our framework and its potential contribution remains an open question that could be addressed in future work.","revision_made":"yes","referee_comment":"The claim that the reaction 'serves as an excellent instrument to probe the nature of low-lying Σ states' because 'only resonances that are dynamically generated by these interactions show up' is not fully justified. The amplitudes are constructed entirely from meson-baryon scattering amplitudes, so the absence of the Σ(1385) is guaranteed by the model's inputs rather than derived as a consequence of isospin-violating dynamics. A direct isospin-violating J/ψ → Λ̄Σ*(1385) → Λ̄Λπ⁰ vertex is not discussed or bounded."},{"response":"This is a fair point. We agree that the triangle mechanism of Ref. [21] could in principle produce a Σ(1430) signal in the πΛ spectrum through a different topology, and that its dismissal on the grounds of unknown branching ratios is insufficient. We will expand the discussion in §I to address this more carefully. Regarding an upper bound: since the J/ψ → Σ̄*Σ branching ratios are unknown, a model-independent upper bound is not feasible without additional assumptions. However, we can discuss the question of experimental distinguishability. The two mechanisms differ in their angular distributions: the triangle mechanism involves a specific kinematic configuration (triangle singularity) that imposes characteristic angular correlations, while our rescattering mechanism produces a more isotropic distribution in the rest frame. Additionally, the triangle mechanism of Ref. [21] predicts a signal in the π⁺Λ (or π⁻Λ) channel but not simultaneously in both π⁰Λ and π⁰Λ̄ with equal strength, whereas our mechanism produces both symmetrically. We will add a discussion of these distinguishing features and acknowledge that, without a quantitative estimate of the triangle contribution, the uniqueness of our interpretation cannot be fully established at present.","revision_made":"partial","referee_comment":"The competing triangle mechanism (J/ψ → Σ̄*Σ, followed by Σ̄* → Λ̄π and πΣ fusion) is mentioned but dismissed because the J/ψ → Σ̄*Σ branching ratios are unknown. This mechanism could produce the same Σ(1430) signal through a very different topology, undermining the uniqueness of the interpretation. The authors should estimate an upper bound or discuss whether the two mechanisms can be distinguished experimentally."},{"response":"We agree completely. The statement that the data show a structure 'reproduced by the theory' overstates what the limited statistics support. We will revise the language to state that the data are consistent with the theoretical prediction but do not constitute evidence for it. Regarding the background: the smooth background shown in Fig. 4 is taken from the experimental fit of Ref. [18] and is not derived from our theoretical framework. Within our formalism, the non-resonant rescattering amplitudes (the smooth parts of the meson-baryon t-matrices away from the Σ(1430) pole) do contribute to the mass distribution, but we have not attempted to decompose our prediction into 'resonant' and 'non-resonant' pieces in a way that could replace the phenomenological background. We will clarify in the revised manuscript that the background is phenomenological, taken from the experimental analysis, and that a first-principles prediction of the full mass distribution including non-resonant contributions is beyond the scope of the present work.","revision_made":"yes","referee_comment":"The comparison with BESIII data is overstated. The 'signal' at 1430 MeV consists of a single data point above a smooth background that is itself taken from the experimental fit rather than derived from the theoretical framework. The statement that 'the data show a structure around M_{πΛ} = 1430 MeV that is reproduced by the theory' should be tempered. The authors should also clarify the physical origin of the smooth background."}],"tokens_in":10700,"tokens_out":1215,"duration_ms":180118,"standing_objections":[]},"desk_editor":{"model":"glm-5.2","letter":"The main thing to know: this paper applies the chiral unitary SU(3) framework to J/ψ→ΛΛ̄π⁰ and predicts that the dynamically-generated Σ(1430)(1/2⁻) should appear in the πΛ spectrum while the conventional Σ(1385)(3/2⁺) should not. The comparison with BESIII data is suggestive but statistically very weak — essentially one data point above background near 1430 MeV and no visible Σ(1385) signal. The authors are honest about this limitation, which is to their credit. The formalism is clean and internally consistent. The SU(3) singlet construction, the identification of the two surviving trace structures, and the reduction to the amplitudes in Eqs. (11)–(12) are straightforward and correct within the stated assumptions. The ratio Ã/B=1.44 is taken from prior work (Refs. [26, 29]), leaving only a global normalization and a smooth background as free parameters. That is a reasonable parameter budget. The observation that the Σ(1385) is absent from the BESIII data — when it dominates other πΛ spectra — is genuinely interesting and worth noting. Now the soft spots. The stress-test concern about circularity has real force. The amplitudes are built entirely from meson-baryon scattering amplitudes t_{MB,M'B'} taken from chiral unitary coupled-channel approaches. The Σ(1385)(3/2⁺) is a qqq state that does not appear as an S-wave pole in these amplitudes, so its absence is guaranteed by construction — not independently predicted. The paper does not show that a generic isospin-violating J/ψ→Λ̄Λπ⁰ amplitude must suppress qqq states; it shows that their specific rescattering topology, which uses only meson-baryon unitarized amplitudes, naturally misses them. If there is a direct isospin-violating J/ψ→Λ̄Σ*(1385)→Λ̄Λπ⁰ coupling not mediated by meson-baryon rescattering, this framework would not capture it. The authors briefly acknowledge the competing triangle mechanism of Ref. [21] but set it aside due to unknown branching ratios. That is defensible given the current state of knowledge, but it leaves the 'excellent instrument to probe the nature of low-lying Σ states' claim oversold. The experimental comparison (Fig. 4) is too sparse to independently validate the mechanism. One data point above background is not a confirmation, and the authors say so themselves. This is a paper for hadron spectroscopy theorists and experimentalists working on BESIII charm decays. It provides a concrete, falsifiable prediction that future high-statistics J/ψ data can test. The framework is standard for this group and well-executed, the prediction is new and specific, and the call for better data is well-placed. The circularity concern is real but does not invalidate the calculation — it limits the strength of the interpretive claim. This deserves a serious referee. The referee should push the authors to soften the 'filter' language and to discuss more carefully what would happen if non-rescattering isospin-violating mechanisms were included.","headline":"Clean formalism, suggestive but thin data comparison, and a 'filter' claim that is partly circular","tokens_in":11469,"tokens_out":739,"would_cite":false,"duration_ms":99167,"reading_group":"no","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":["13.25.Gv","14.20.Jn","12.39.Fe"],"model":"glm-5.2","headline":"Isospin-violating J/ψ decay filters for molecular baryons","keywords":["isospin violation","dynamically generated resonances","Σ(1430)","chiral unitary approach","SU(3) singlet","J/ψ decay","meson-baryon interaction","baryon spectroscopy"],"falsifier":"High-statistics BESIII data showing a clear Σ(1385) peak in the Λπ⁰ invariant mass spectrum of J/ψ→ΛΛ̄π⁰, or showing a line shape inconsistent with the Σ(1430) rescattering prediction, would falsify the central claim.","tokens_in":10892,"feed_emoji":"🔬","tokens_out":1370,"duration_ms":98882,"temperature":0.7,"pith_summary":"This paper argues that the isospin-violating decay J/ψ→ΛΛ̄π⁰ selectively produces the Σ(1430)(1/2⁻), a state dynamically generated from meson-baryon interactions, while suppressing the Σ(1385)(3/2⁺), a conventional three-quark state. The mechanism works as follows: the J/ψ is a flavor singlet under SU(3), so the initial baryon-antibaryon-meson combinations that form the decay vertex are all isospin-conserving. The ΛΛ̄π⁰ final state arises only through final-state rescattering, and isospin is broken because particles within the same isospin multiplet (e.g., π⁺, π⁻, π⁰ or Σ⁺, Σ⁻, Σ⁰) have slightly different masses, preventing exact cancellation of loop amplitudes. Because the final state is reached exclusively through hadronic rescattering, only resonances that are themselves products of hadronic interactions—dynamically generated resonances—can appear. The Σ(1430) is such a state; the Σ(1385) is not. The authors compute the Λπ⁰ invariant mass distribution using chiral unitary amplitudes for the meson-baryon scattering, with a single free normalization parameter, and compare to existing BESIII data. The data show a hint of structure near 1430 MeV and no visible Σ(1385) peak, consistent with the prediction. The paper calls for higher-statistics measurements to confirm the pattern.","feed_headline":"Isospin-violating J/ψ decay acts as a filter for molecular baryons","feed_subtitle":"Only dynamically generated resonances appear in J/ψ→ΛΛ̄π⁰; the conventional Σ(1385) is predicted absent, and limited data agree.","key_machinery":"The central mechanism is the SU(3)-singlet rescattering topology: the J/ψ couples equally to all baryon-antibaryon-meson singlet combinations, and the ΛΛ̄π⁰ final state emerges only after meson-baryon (or meson-antibaryon) rescattering. Isospin violation enters because the loop amplitudes for different charge channels within the same isospin multiplet fail to cancel when physical masses are used. The scattering amplitudes themselves come from chiral unitary coupled-channel theory, which generates the Σ(1430) as a near-threshold pole in the K̄N, πΣ, πΛ, ηΣ, ηΛ, KΞ coupled channels.","core_discovery":"The paper identifies a selection rule: in isospin-violating decays driven by final-state rescattering from an SU(3)-singlet initial state, only dynamically generated resonances—those arising from meson-baryon interactions rather than from the strong interaction binding of three quarks—can appear in the invariant mass spectrum. Applied to J/ψ→ΛΛ̄π⁰, this rule predicts the Σ(1430)(1/2⁻) is visible and the Σ(1385)(3/2⁺) is absent, a pattern the limited BESIII data do not contradict.","pith_inferences":["The paper dismisses a competing triangle-singularity mechanism proposed elsewhere because unknown branching ratios prevent quantitative comparison. A natural extension would be to measure or bound the J/ψ→Σ̄*Σ branching ratios needed to evaluate that alternative, which would determine whether the two mechanisms produce distinguishable line shapes or interfere.","If the selection rule holds broadly, one could construct a systematic classification scheme: for each known or candidate baryon resonance, identify an isospin-violating J/ψ decay channel where the resonance's coupled channels appear, and use presence or absence in the spectrum as a binary diagnostic of its dynamical origin.","The paper notes that a prior triangle-singularity prediction for a related reaction overestimated the experimental peak by a factor of 40. This suggests that triangle singularities in this kinematic regime may be systematically overestimated, strengthening the case that the rescattering mechanism dominates—but a direct comparison of the two mechanisms in the same channel would settle the question."],"forward_implications":["If higher-statistics BESIII data confirm a Σ(1430) peak and continued absence of Σ(1385) in J/ψ→ΛΛ̄π⁰, it would validate the claim that isospin-violating decays serve as a clean filter for dynamically generated baryon resonances.","The same selection rule can be applied to other isospin-violating J/ψ decays to classify additional baryon states as molecular or three-quark in nature, extending the diagnostic tool beyond the Σ sector.","If the hypothetical Σ(1380)(1/2⁻) exists and is not dynamically generated, it should also be absent from this reaction, providing a test of its nature through non-observation.","The framework can be extended to the Λ(1405) double-pole structure, since the SU(3)-singlet filter may distinguish the two overlapping poles if applied to appropriate isospin-violating channels."],"fun_headline_variants":["Only molecular baryons appear in isospin-violating J/ψ decay","Σ(1430) shows up in J/ψ→ΛΛ̄π⁰; conventional Σ(1385) does not","Isospin-violating J/ψ decay filters dynamically generated resonances","BESIII data agree: Σ(1430) visible, Σ(1385) absent in J/ψ decay"],"cache_read_input_tokens":0,"weakest_assumption_plain":"The prediction relies on the assumption that the SU(3)-singlet rescattering topology is the dominant mechanism for this isospin-violating decay. If other isospin-breaking mechanisms contribute substantially—such as direct η-π⁰ mixing, triangle singularities with unknown branching ratios, or different production topologies—the clean filter property distinguishing dynamically generated from conventional resonances could be compromised.","fun_headline_variants_meta":{"raw":{"variants":["Only molecular baryons appear in isospin-violating J/ψ decay","Σ(1430) shows up in J/ψ→ΛΛ̄π⁰; conventional Σ(1385) does not","Isospin-violating J/ψ decay filters dynamically generated resonances","BESIII data agree: Σ(1430) visible, Σ(1385) absent in J/ψ decay"]},"model":"glm-5.2","effort":"high","cost_usd":0.0,"raw_usage":{"total_tokens":743,"prompt_tokens":640,"completion_tokens":103,"prompt_tokens_details":null},"tokens_in":640,"tokens_out":103,"duration_ms":36223,"temperature":1.0,"reasoning_tokens":null,"cache_read_input_tokens":0,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-08T11:46:34.465552+00:00","model_set":{"reader":"glm-5.2"},"falsifier":"High-statistics BESIII data showing a clear Σ(1385) peak in the Λπ⁰ invariant mass spectrum of J/ψ→ΛΛ̄π⁰, or showing a line shape inconsistent with the Σ(1430) rescattering prediction, would falsify the central claim.","supporting_citations":[],"review_version":1}