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REVIEW 3 major objections 4 minor 63 references

Hadronic matter beats quark matter up to eight times nuclear density in a self-consistent parity-doublet treatment.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

In a parity doublet model, self-consistent minimization keeps the quark fraction at zero up to about 8n0, showing quark onset and chiral restoration need not coincide.

T0 review reviewed 2026-08-05 challenge →

load-bearing objection The parity-doublet + quarkyonic/baryquark setup is new, but the main result rests on an ω-coupling inconsistency in Sec. IV. the 3 major comments →

arxiv 2509.03138 v1 pith:TCXGDRCX submitted 2025-09-03 nucl-th hep-ph

Suppression of dynamical momentum-space shell by chiral symmetry

classification nucl-th hep-ph
keywords quarkyonic matterbaryquark matterparity doublet modelchiral symmetry restorationmomentum-space shelldense nuclear matterequation of statequark onset
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

At very high density, the neutrons inside a compact star may dissolve into quarks, and the order in which hadrons and quarks fill momentum space decides whether that happens. This paper tries to settle the question in a parity doublet model of chiral symmetry, comparing quarkyonic matter—quarks filling states below a hadronic shell—with baryquark matter—hadrons filling states below a quark shell. Its central result is that once the shell width is fixed self-consistently by minimizing the free energy, baryquark matter always beats quarkyonic matter, yet purely hadronic matter beats both until roughly eight times nuclear saturation density. Only at the boundary of the model's validity does a small quark admixture, about 4 percent, first become favorable. If correct, the onset of quark degrees of freedom and the restoration of chiral symmetry are distinct events: chiral symmetry can be restored while the matter remains purely hadronic.

Core claim

At fixed baryon density, the shell width separating baryon and quark Fermi seas is fixed by minimizing energy over the quark fraction Yq. Under this self-consistent rule, baryquark matter (nucleons inside, quarks outside) always beats quarkyonic matter (quarks inside, nucleon shell outside), but both lose to purely hadronic matter throughout the model's domain. The mechanism: the ω repulsion is locked to total baryon density, so swapping nucleons for quarks never removes the repulsion, while σ attraction keeps chiral symmetry broken as long as nucleons dominate. A tiny quark fraction (Yq≈0.04) becomes favorable in the baryquark geometry only at the boundary nB≈8n0—the authors' evidence that

What carries the argument

The central object is the momentum-space shell width Δ, the momentum gap between the baryonic and quark Fermi seas. Earlier work parametrized it by hand; here it is generated dynamically by minimizing the energy density at fixed baryon density with respect to the quark fraction Yq, equivalent to an extra gap equation. This dynamical shell makes the quarkyonic and baryquark geometries directly comparable at equal Fermi momentum. The mechanism that carries the argument is the parity-doublet mean field: the ω gap equation fixes the repulsive vector field from total baryon density, so the pure-quark limit still carries the hadronic repulsion, and the σ field's attraction pushes the minimum to Yq

Load-bearing premise

The central claim collapses if quarks do not inherit the nucleon's vector repulsion: the model fixes the ω field by total baryon density, so a pure quark phase still pays the hadronic repulsion; relax that and the energy minimum moves to finite quark fraction at moderate densities.

What would settle it

Compute the same free-energy minimization at nB=4n0 with the quark vector coupling set to zero while leaving hadronic couplings fixed: a minimum at finite quark fraction would invert the central conclusion. Observationally, neutron-star mass-radius data that require a softening (quark) contribution below about 5n0 would contradict the paper's hadronic-dominance claim.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • Within the model, equations of state for compact stars should be purely hadronic up to several times saturation density; quark admixtures do not lower the free energy before roughly 8n0.
  • Wherever a mixed phase does appear, the baryquark arrangement—nucleons in the core, quarks in the shell—is the one the energy selects.
  • Chiral symmetry restoration and quark deconfinement are not tied: observing the chiral condensate dropping does not imply quarks have appeared.
  • At roughly 8n0 the quark onset coincides with the expected onset of the negative-parity chiral partner N(1535), so the model's own validity ends where quarks start.
  • Differences from excluded-volume models trace to the persistent ω repulsion in the quark phase; removing that repulsion restores an early quark onset.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • A quark vector coupling weaker than the nucleon's is a natural, untested modification that could move the free-energy minimum to finite Yq at moderate density; the paper only explores the shared-coupling case.
  • The model suggests a practical diagnostic: an equation of state that stays stiff and purely hadronic up to roughly 8n0 will look very different from one with a quark shell, so neutron-star mass-radius data in the 2–5n0 range can discriminate between shared- and separate-repulsion scenarios.
  • The near-coincidence of quark onset and N(1535) onset at 8n0 hints that both thresholds may be the same phenomenon: once Pauli blocking fails, the chiral partner and quarks become available together, a coupling a future model with both active could test.
  • The paper's future-work list—diquark pairing, color superconductivity, finite isospin asymmetry—is where a finite-Yq minimum could plausibly reappear; this work isolates the clean mean-field baseline.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 4 minor

Summary. The manuscript embeds two schematic momentum-space configurations for dense isospin-symmetric matter, quarkyonic and baryquark, in an SU(2) parity doublet mean-field model. The momentum-space shell width is treated dynamically by fixing the total baryon density and minimizing the energy density with respect to the quark fraction Y_q. The authors report that baryquark matter is energetically favored over quarkyonic matter, but that both are disfavored compared to purely hadronic matter up to n_B ≈ 8 n_0, with the first finite-Y_q minimum appearing only near that upper boundary. They conclude that quark degrees of freedom play no significant role within the model's domain of applicability and that the onset of quarks is decoupled from chiral symmetry restoration.

Significance. If the result were established, it would have direct bearing on hadron-quark crossover scenarios for neutron-star matter and on the expected correlation between chiral restoration and deconfinement. The self-consistent treatment of the momentum-space shell and the systematic comparison of quarkyonic versus baryquark topologies are useful and go beyond earlier fixed-shell studies. However, the central conclusion is currently not supported by the printed thermodynamic potential, because the quark sector is not coupled to the omega field while the text claims that the omega repulsion persists in the pure-quark limit. The manuscript also contains an incorrect statement about the momentum-shell identity. These issues must be resolved before the significance of the claimed decoupling can be assessed.

major comments (3)
  1. [Secs. II.A, II.B and IV] There is a direct contradiction between the displayed formulas and the central mechanism. In Eqs. (7) and (14) the quark chemical potential enters as μ_q = μ_B/N_c with no ω coupling, while the nucleon potentials in Eqs. (6) and (13) use μ_N = μ_B − g_ω ω. The gap equation ∂Ω/∂ω = 0 therefore gives m_ω^2 ω = g_ω n_N, not g_ω n_B. At Y_q = 1, n_N = 0 and ω = 0, so the pure-quark state is a free quark gas plus the σ field. This contradicts the text in Sec. IV: 'the ω mean field remains fixed at given baryon density' and 'the repulsive ω contribution persists even in the pure quark phase at Y_q = 1'. Since the claimed Y_q = 0 minimum relies on this persistent repulsion, the printed formalism does not support the paper's main result. The authors must either add an explicit quark-ω coupling to Ω_q and redo the minimization, or remove the claim that vector repulsion persists in the pure-quark
  2. [Sec. IV, middle panel of Fig. 3] The statement that 'the momentum shells are identical in the quarkyonic and baryquark scenarios' does not follow from the density relations. For baryquark matter, Eqs. (15)–(16) give n_B = (2/3π^2)[Δ^3 + (k_F^3 − Δ^3)/N_c^3] for k_F > Δ, whereas for quarkyonic matter, Eqs. (10)–(11) give n_B = (2/3π^2)[k_F^3 − (1 − N_c^{−3})(k_F − Δ)^3]. At fixed n_B and Y_q these are different algebraic relations for Δ; the claimed derivation from k_F^3 = 3π^2 n_B/2 is only valid in the pure-hadronic limit Y_q = 0. If the numerical minimization nonetheless imposed identical Δ in both scenarios, then it is not the minimization described by Eqs. (5)–(16); if it did not, the text is misleading and the displayed overlapping curves require explanation.
  3. [Sec. IV, n_B ≈ 8 n_0 onset] The finite-Y_q minimum in the baryquark model is found at n_B ≈ 8 n_0, which the authors themselves identify as the border of applicability of the model, set by the expected onset of the negative-parity N(1535) partner and by the quark-chemical-potential window Λ_QCD < μ_q < √N_c Λ_QCD. Thus the conclusion 'the contribution of quarks is not relevant within the model's domain of applicability' relies on a single point at the edge of that domain. To make the central claim robust, the authors should either extend the calculation beyond this boundary (e.g., by including the negative-parity state) or demonstrate explicitly that the quark onset is not simply a boundary artifact.
minor comments (4)
  1. [Throughout] There are several typos and inconsistencies in notation: 'the the chirally invariant mass', 'os the baryon density increases', 'mvaq N /3' instead of m_N^{vac}/3, and 'quarks populate states inside the nucleonic Fermi sea' in the abstract versus the later definition of baryquark matter.
  2. [Sec. II] The text states that the negative-parity state is neglected for n_N ≲ 8 n_0, but later the onset is quoted at n_B = 8 n_0. Since n_N differs from n_B once quarks are present, the applicability condition should be stated in terms of the variable actually used in the calculation.
  3. [Sec. IV] The statement 'Due to the gap equation, the vector mean field ω ∝ n_B' is asserted without derivation and, as noted in the major comments, is inconsistent with Eqs. (6), (7), (13), and (14). This sentence should be removed or replaced by a consistent derivation once the quark-ω coupling is specified.
  4. [Figs. 3 and 4] The black dots and triangles in the figures are described in the captions as marking onsets for specific quark-mass choices, but the reader is not told how these onsets are determined numerically (e.g., from the second derivative of the energy density or from the position of the local minimum). A brief definition would improve reproducibility.

Circularity Check

0 steps flagged

No circularity: the Yq=0 minimum is a genuine variational result from the printed thermodynamic potential; the Sec. IV omega-statement is an internal-consistency issue, not an input-output equivalence.

full rationale

The central quantity Yq is a free variational parameter: the paper evaluates the thermodynamic potential of Eqs. (1)-(19) at fixed baryon density and minimizes over Yq, so the Yq=0 minimum is a computed outcome, not a fitted parameter renamed as a prediction. The quark chemical potential μq=μB/Nc, the shell occupations, and the quark-mass ansatz mq=mN/3 are stated model inputs; the paper explicitly varies the quark mass (mN/50, free-quark case) and finds the qualitative conclusion unchanged, so the result is not an artifact of a single hidden fit. Self-citations (Refs. [20,49,62]) supply the model framework and mass/momentum-space ansaetze, but those are inputs, not theorems invoked to force the result; no uniqueness claim is imported. One internal inconsistency should be flagged but does not constitute circularity: Sec. IV states 'the vector mean field ω ∝ n_B' and 'the repulsive ω contribution persists even in the pure quark phase at Yq=1', whereas the displayed Eqs. (6)-(7) give quarks no ω coupling (μq=μB/Nc with no -gωω/Nc term), so ∂Ω/∂ω=0 would yield mω^2 ω = gω n_N and ω=0 at Yq=1. If the intended calculation included quark-ω coupling, that term is absent from the printed potential; if not, the explanatory mechanism in Sec. IV is unsupported. Either way, this is a consistency/correctness issue rather than a case in which a 'prediction' reduces by construction to its own input.

Axiom & Free-Parameter Ledger

5 free parameters · 6 axioms · 0 invented entities

The central result rests on five fitted or chosen parameters (couplings calibrated to saturation, m0, mq, Λ_QCD, α) and six structural assumptions. Two of these, the shared vector repulsion (μq = μB/Nc) and the quark mass duality (mq = mN/3), are paper-specific and jointly produce the suppression of quarks; the domain bound (n ≤ 8n0) sets the range where the conclusion can be tested. No new particles, forces, dimensions, or conserved quantities are introduced; the baryquark configuration is adopted from Ref. [39].

free parameters (5)
  • PDM mean-field couplings (μ̄², λ4, λ6, gω) = not tabulated; fixed by nuclear saturation properties (n0 = 0.16 fm^-3)
    Standard RMF calibration; determines the stiffness of the hadronic equation of state and hence how hard it is for the quark sector to compete.
  • chiral invariant mass m0 = 800 MeV
    Chosen input from prior parity doublet studies; authors state results are qualitatively robust against variations.
  • constituent quark mass mq = mN/3 (also mN/50 and vacuum-fixed variants)
    Ad hoc duality ansatz (Eq. 17); changing it moves the quark onset but not the qualitative suppression within the domain.
  • Λ_QCD = 300 MeV
    Scale choice entering the shell parametrization (Eq. 18) and the validity window Λ_QCD < μq < √Nc Λ_QCD.
  • shell exponent α (Section III only) = 0, 1, 2, 3 (scanned)
    Scanned in the parametrized-shell study; large α violates thermodynamic consistency, flagged by the authors; not used in the main self-consistent treatment.
axioms (6)
  • domain assumption Parity doublet structure: N(939) and N(1535) are chiral partners with masses from Eq. (4)
    Foundation of the parity doublet model; introduced in Sec. II with couplings g1, g2 fixed by vacuum masses and m0.
  • domain assumption Relativistic mean-field approximation at T = 0 with σ and ω mean fields
    Sec. II, Eq. (1); standard for this model class.
  • domain assumption Negative-parity partner N(1535) is absent for nN ≤ 8n0 due to Pauli blocking of excited baryons
    Sec. II; sets the upper density boundary of the model; the quark onset is found at this boundary.
  • domain assumption Quarkyonic and baryquark pictures are valid only in Λ_QCD < μq < √Nc Λ_QCD
    Sec. II; with Λ_QCD = 300 MeV, the 8n0 point (μB ≈ 1.5 GeV) sits at the upper edge of the window.
  • ad hoc to paper Quarks share the baryon chemical potential and the ω repulsion: μq = μB/Nc, with ω fixed by nB even at Yq = 1
    Sec. IV; the structural difference from Ref. [39] and the main driver of the suppression result.
  • ad hoc to paper Constituent quark mass tied to the medium-dependent nucleon mass, mq = mN/3 (Eq. 17)
    Sec. II B; asserted hadron-quark duality; sensitivity explored with mq = mN/50.

reviewed 2026-08-05 · how reviews work

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Cite this review

Pith. "Pith review of Suppression of dynamical momentum-space shell by chiral symmetry." pith.science (2026). https://pith.science/paper/TCXGDRCX

@misc{pith2026250903138,
  author       = {Pith},
  title        = {Pith review of: Suppression of dynamical momentum-space shell by chiral symmetry},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/TCXGDRCX}},
  note         = {Machine review of arXiv:2509.03138}
}
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read the original abstract

We investigate the appearance of quark degrees of freedom in dense isospin-symmetric nuclear matter. We employ the parity doublet model to incorporate chiral dynamics. Specifically, we contrast quarkyonic matter, in which quarks occupy states above the nucleon Fermi surface, with baryquark matter, in which quarks populate states inside the nucleonic Fermi sea. We find that while baryquark matter is generally energetically favored over quarkyonic matter, the self-consistent treatment of the momentum-space shell reveals that purely hadronic matter provides the lowest free energy up to densities well beyond nuclear saturation. Consequently, the contribution of quarks is not relevant within the model's domain of applicability, even though chiral symmetry becomes restored. This demonstrates that the onset of quark degrees of freedom and the restoration of chiral symmetry need not coincide.

Figures

Figures reproduced from arXiv: 2509.03138 by Bikai Gao, Micha{\l} Marczenko.

Figure 1
Figure 1. Figure 1: FIG. 1. Schematic plot showing the structure of the Fermi [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Normalized baryon number density [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Energy density (top panel), momentum shell (middle [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗

discussion (0)

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Reference graph

Works this paper leans on

63 extracted references · 31 canonical work pages · 24 internal anchors

  1. [1]

    M. C. Miller et al., The Radius of PSR J0740+6620 from NICER and XMM-Newton Data, Astrophys. J. Lett. 918, L28 (2021), arXiv:2105.06979 [astro-ph.HE]

  2. [2]

    T. E. Riley, A. L. Watts, P. S. Ray, S. Bogdanov, S. Guillot, S. M. Morsink, A. V. Bilous, Z. Arzouma- nian, D. Choudhury, J. S. Deneva, K. C. Gendreau, A. K. Harding, W. C. G. Ho, J. M. Lattimer, M. Loewen- stein, R. M. Ludlam, C. B. Markwardt, T. Okajima, C. Prescod-Weinstein, R. A. Remillard, M. T. Wolff, E. Fonseca, H. T. Cromartie, M. Kerr, T. T. Pen...

  3. [3]

    B. P. Abbott et al. (LIGO Scientific, Virgo), GW170817: Observation of Gravitational Waves from a Binary Neu- tron Star Inspiral, Phys. Rev. Lett. 119, 161101 (2017), arXiv:1710.05832 [gr-qc]

  4. [4]

    B. P. Abbott et al. (LIGO Scientific, Virgo, Fermi GBM, INTEGRAL, IceCube, AstroSat Cadmium Zinc Telluride Imager Team, IPN, Insight-Hxmt, ANTARES, Swift, AGILE Team, 1M2H Team, Dark Energy Camera GW-EM, DES, DLT40, GRA WITA, Fermi-LAT, ATCA, ASKAP, Las Cumbres Observatory Group, OzGrav, DWF (Deeper Wider Faster Program), AST3, CAAS- TRO, VINROUGE, MASTER...

  5. [5]

    C. H. Lenzi and G. Lugones, Hybrid stars in the light of the massive pulsar PSR J1614-2230, Astrophys. J. 759, 57 (2012), arXiv:1206.4108 [astro-ph.SR]

  6. [6]

    Benic, D

    S. Benic, D. Blaschke, D. E. Alvarez-Castillo, T. Fischer, and S. Typel, A new quark-hadron hybrid equation of state for astrophysics - I. High-mass twin compact stars, Astron. Astrophys. 577, A40 (2015), arXiv:1411.2856 [astro-ph.HE]

  7. [7]

    G¨ artlein, O

    C. G¨ artlein, O. Ivanytskyi, V. Sagun, and D. Blaschke, Hybrid star phenomenology from the properties of the special point, Phys. Rev. D 108, 114028 (2023), arXiv:2301.10765 [nucl-th]

  8. [8]

    J. P. Carlomagno, G. A. Contrera, A. G. Grunfeld, and D. Blaschke, Thermal twin stars within a hybrid equation of state based on a nonlocal chiral quark model compat- ible with modern astrophysical observations, Phys. Rev. D 109, 043050 (2024), arXiv:2312.01975 [nucl-th]

  9. [9]

    Ayriyan, D

    A. Ayriyan, D. Blaschke, J. P. Carlomagno, G. A. Con- trera, and A. G. Grunfeld, Bayesian Analysis of Hybrid Neutron Star EOS Constraints Within an Instantaneous Nonlocal Chiral Quark Matter Model, Universe 11, 141 (2025), arXiv:2501.00115 [nucl-th]

  10. [10]

    Gao, W.-L

    B. Gao, W.-L. Yuan, M. Harada, and Y.-L. Ma, Ex- ploring the first-order phase transition in neutron stars using the parity doublet model and a Nambu–Jona- Lasinio–type quark model, Phys. Rev. C 110, 045802 (2024), arXiv:2407.13990 [nucl-th]

  11. [11]

    Christian, I

    J.-E. Christian, I. A. Rather, H. Gholami, and M. Hof- mann, Comprehensive Analysis of Constructing Hy- brid Stars with an RG-consistent NJL Model (2025), arXiv:2503.13626 [astro-ph.HE]

  12. [12]

    Z. Yang, T. Zeng, Y. Yan, W.-L. Yuan, C. Zhang, and E. Zhou, Hybrid Quark Stars with Quark-Quark Phase Transitions (2025), arXiv:2507.00776 [astro-ph.HE]

  13. [13]

    Masuda, T

    K. Masuda, T. Hatsuda, and T. Takatsuka, Hadron-Quark Crossover and Massive Hybrid Stars with Strangeness, Astrophys. J. 764, 12 (2013), arXiv:1205.3621 [nucl-th]

  14. [14]

    Masuda, T

    K. Masuda, T. Hatsuda, and T. Takatsuka, Hadron–quark crossover and massive hybrid stars, PTEP 2013, 073D01 (2013), arXiv:1212.6803 [nucl-th]

  15. [15]

    T. Kojo, P. D. Powell, Y. Song, and G. Baym, Phe- nomenological QCD equation of state for massive neutron stars, Phys. Rev. D 91, 045003 (2015), arXiv:1412.1108 [hep-ph]

  16. [16]

    G. Baym, T. Hatsuda, T. Kojo, P. D. Powell, Y. Song, and T. Takatsuka, From hadrons to quarks in neutron stars: a review, Rept. Prog. Phys. 81, 056902 (2018), arXiv:1707.04966 [astro-ph.HE]

  17. [17]

    G. Baym, S. Furusawa, T. Hatsuda, T. Kojo, and H. Togashi, New Neutron Star Equation of State with Quark-Hadron Crossover, Astrophys. J. 885, 42 (2019), arXiv:1903.08963 [astro-ph.HE]

  18. [18]

    Blaschke, E

    D. Blaschke, E. O. Hanu, and S. Liebing, Neutron stars with crossover to color superconducting quark matter, Phys. Rev. C 105, 035804 (2022), arXiv:2112.12145 8 [nucl-th]

  19. [19]

    T. Kojo, G. Baym, and T. Hatsuda, Implications of NICER for Neutron Star Matter: The QHC21 Equation of State, Astrophys. J. 934, 46 (2022), arXiv:2111.11919 [astro-ph.HE]

  20. [20]

    Quark-hadron crossover equations of state for neutron stars: constraining the chiral invariant mass in a parity doublet model

    T. Minamikawa, T. Kojo, and M. Harada, Quark-hadron crossover equations of state for neutron stars: constrain- ing the chiral invariant mass in a parity doublet model, Phys. Rev. C 103, 045205 (2021), arXiv:2011.13684 [nucl-th]

  21. [21]

    Y. K. Kong, T. Minamikawa, and M. Harada, Neutron star matter based on a parity doublet model including the a0(980) meson, Phys. Rev. C 108, 055206 (2023), arXiv:2306.08140 [nucl-th]

  22. [22]

    Y.-K. Kong, B. Gao, and M. Harada, Chiral Invari- ant Mass Constraints from HESS J1731 347 in an Ex- tended Parity Doublet Model with Isovector Scalar Me- son (2025), arXiv:2506.16684 [nucl-th]

  23. [23]

    McLerran and R

    L. McLerran and R. D. Pisarski, Phases of cold, dense quarks at large N(c), Nucl. Phys. A 796, 83 (2007), arXiv:0706.2191 [hep-ph]

  24. [24]

    McLerran, K

    L. McLerran, K. Redlich, and C. Sasaki, Quarkyonic Matter and Chiral Symmetry Breaking, Nucl. Phys. A 824, 86 (2009), arXiv:0812.3585 [hep-ph]

  25. [25]

    Hidaka, L

    Y. Hidaka, L. D. McLerran, and R. D. Pisarski, Baryons and the phase diagram for a large number of colors and flavors, Nucl. Phys. A 808, 117 (2008), arXiv:0803.0279 [hep-ph]

  26. [26]

    The Quarkyonic Star

    K. Fukushima and T. Kojo, The Quarkyonic Star, As- trophys. J. 817, 180 (2016), arXiv:1509.00356 [nucl-th]

  27. [27]

    D. C. Duarte, S. Hernandez-Ortiz, K. S. Jeong, and L. D. McLerran, Quarkyonic effective field theory, quark- nucleon duality, and ghosts, Phys. Rev. D 104, L091901 (2021), arXiv:2103.05679 [nucl-th]

  28. [28]

    Kojo, Stiffening of matter in quark-hadron continu- ity, Phys

    T. Kojo, Stiffening of matter in quark-hadron continu- ity, Phys. Rev. D 104, 074005 (2021), arXiv:2106.06687 [nucl-th]

  29. [29]

    McLerran and S

    L. McLerran and S. Reddy, Quarkyonic Matter and Neutron Stars, Phys. Rev. Lett. 122, 122701 (2019), arXiv:1811.12503 [nucl-th]

  30. [30]

    K. S. Jeong, L. McLerran, and S. Sen, Dynamically gener- ated momentum space shell structure of quarkyonic mat- ter via an excluded volume model, Phys. Rev. C 101, 035201 (2020), arXiv:1908.04799 [nucl-th]

  31. [31]

    Finite-Temperature Quarkyonic Matter with an Excluded Volume Model

    S. Sen and N. C. Warrington, Finite-temperature quarky- onic matter with an excluded volume model, Nucl. Phys. A 1006, 122059 (2021), arXiv:2002.11133 [nucl-th]

  32. [32]

    Fujimoto, T

    Y. Fujimoto, T. Kojo, and L. D. McLerran, Momentum Shell in Quarkyonic Matter from Explicit Duality: A Dual Model for Cold, Dense QCD, Phys. Rev. Lett. 132, 112701 (2024), arXiv:2306.04304 [nucl-th]

  33. [33]

    Fujimoto, T

    Y. Fujimoto, T. Kojo, and L. McLerran, Quarky- onic matter pieces together the hyperon puzzle (2024), arXiv:2410.22758 [nucl-th]

  34. [35]

    Quarkyonic picture of isospin QCD

    O. Ivanytskyi, Quarkyonic picture of isospin QCD (2025), arXiv:2505.07076 [nucl-th]

  35. [36]

    Ferromagnetic instabilities in quarkyonic matter

    B. Gao and K. Yoshida, Ferromagnetic instabilities in quarkyonic matter (2025), arXiv:2507.06577 [nucl-th]

  36. [37]

    Kojo, Stiffening of matter in quark–hadron continu- ity: A mini-review, J

    T. Kojo, Stiffening of matter in quark–hadron continu- ity: A mini-review, J. Subatomic Part. Cosmol. 4, 100088 (2025), arXiv:2412.20442 [nucl-th]

  37. [38]

    Fujimoto, T

    Y. Fujimoto, T. Kojo, and L. McLerran, Quarkyonic so- lution to the hyperon puzzle, EPJ Web Conf. 316, 07007 (2025)

  38. [39]

    Quarkyonic or baryquark matter? On the dynamical generation of momentum space shell structure

    V. Koch and V. Vovchenko, Quarkyonic or baryquark matter? On the dynamical generation of momentum space shell structure, Phys. Lett. B 841, 137942 (2023), arXiv:2211.14674 [nucl-th]

  39. [40]

    R. V. Poberezhnyuk, H. Stoecker, and V. Vovchenko, Quarkyonic matter with quantum van der Waals the- ory, Phys. Rev. C 108, 045202 (2023), arXiv:2307.13532 [nucl-th]

  40. [41]

    Koch and V

    V. Koch and V. Vovchenko, Quarkyonic or baryquark matter, J. Subatomic Part. Cosmol. 3, 100025 (2025)

  41. [42]

    C. E. Detar and T. Kunihiro, Linear σ Model With Parity Doubling, Phys. Rev. D 39, 2805 (1989)

  42. [43]

    D. Jido, M. Oka, and A. Hosaka, Chiral symmetry of baryons, Prog. Theor. Phys. 106, 873 (2001), arXiv:hep- ph/0110005

  43. [44]

    Marczenko, D

    M. Marczenko, D. Blaschke, K. Redlich, and C. Sasaki, Parity doubling and the dense-matter phase diagram un- der constraints from multi-messenger astronomy, Uni- verse 5, 10.3390/universe5080180 (2019)

  44. [45]

    Yamazaki and M

    T. Yamazaki and M. Harada, Constraint to chiral invari- ant masses of nucleons from gw170817 in an extended parity doublet model, Phys. Rev. C 100, 025205 (2019)

  45. [46]

    The application of the Quark-Hadron Chiral Parity-Doublet Model to neutron star matter

    A. Mukherjee, S. Schramm, J. Steinheimer, and V. Dex- heimer, The application of the Quark-Hadron Chiral Parity-Doublet Model to neutron star matter, Astron. Astrophys. 608, A110 (2017), arXiv:1706.09191 [nucl-th]

  46. [47]

    Reconciling multi-messenger constraints with chiral symmetry restoration

    M. Marczenko, K. Redlich, and C. Sasaki, Reconcil- ing Multi-messenger Constraints with Chiral Symme- try Restoration, Astrophys. J. Lett. 925, L23 (2022), arXiv:2110.11056 [nucl-th]

  47. [48]

    Chiral symmetry restoration and the $\Delta$ matter formation in neutron stars

    M. Marczenko, K. Redlich, and C. Sasaki, Chiral symme- try restoration and ∆ matter formation in neutron stars, Phys. Rev. D 105, 103009 (2022), arXiv:2203.00269 [nucl-th]

  48. [49]

    B. Gao, Y. Yan, and M. Harada, Reconciling constraints from the supernova remnant HESS J1731-347 with the parity doublet model, Phys. Rev. C 109, 065807 (2024), arXiv:2404.04786 [nucl-th]

  49. [50]

    Marczenko, D

    M. Marczenko, D. Blaschke, K. Redlich, and C. Sasaki, Toward a unified equation of state for multi-messenger astronomy, Astron. Astrophys. 643, A82 (2020), arXiv:2004.09566 [astro-ph.HE]

  50. [51]

    Eser and J.-P

    J. Eser and J.-P. Blaizot, Thermodynamics of the parity- doublet model: Symmetric nuclear matter and the chiral transition, Phys. Rev. C 109, 045201 (2024), arXiv:2309.06566 [nucl-th]

  51. [52]

    Eser and J.-P

    J. Eser and J.-P. Blaizot, Thermodynamics of the parity- doublet model. II. Asymmetric and neutron matter, Phys. Rev. C 110, 065205 (2024), arXiv:2408.01302 [nucl-th]

  52. [53]

    Scale symmetry and composition of compact star matter

    L.-Q. Shao and Y.-L. Ma, Scale symmetry and composi- tion of compact star matter, Phys. Rev. D 106, 014014 (2022), arXiv:2202.09957 [nucl-th]

  53. [54]

    Quark structure of isoscalar- and isovector-scalar mesons and nuclear matter property

    Y. Ma and Y.-L. Ma, Quark structure of isoscalar- and isovector-scalar mesons and nuclear matter prop- erty, Phys. Rev. D 109, 074022 (2024), arXiv:2311.07899 [nucl-th]

  54. [55]

    Insights into neutron star equation of state by machine learning

    L.-J. Guo, J.-Y. Xiong, Y. Ma, and Y.-L. Ma, In- sights into Neutron Star Equation of State by Machine Learning, Astrophys. J. 965, 47 (2024), arXiv:2309.11227 [nucl-th]. 9

  55. [56]

    Probing Hadron-quark Transition Through Binary Neutron Star Merger

    L.-J. Guo, W.-C. Yang, Y.-L. Ma, and Y.-L. Wu, Prob- ing Hadron-quark Transition Through Binary Neutron Star Merger, Res. Astron. Astrophys. 25, 035017 (2025), arXiv:2308.01770 [astro-ph.HE]

  56. [57]

    Topology and emergent symmetries in dense compact star matter

    Y.-L. Ma and W.-C. Yang, Topology and Emergent Sym- metries in Dense Compact Star Matter, Symmetry 15, 776 (2023), arXiv:2301.02105 [nucl-th]

  57. [58]

    B. Gao, T. Kojo, and M. Harada, Parity doublet model for baryon octets: Ground states saturated by good di- quarks and the role of bad diquarks for excited states, Phys. Rev. D 110, 016016 (2024), arXiv:2403.18214 [hep- ph]

  58. [59]

    Fluctuations near the liquid-gas and chiral phase transitions in hadronic matter

    M. Marczenko, K. Redlich, and C. Sasaki, Fluctua- tions near the liquid-gas and chiral phase transitions in hadronic matter, Phys. Rev. D 107, 054046 (2023), arXiv:2301.09866 [nucl-th]

  59. [60]

    V. Koch, M. Marczenko, K. Redlich, and C. Sasaki, Fluctuations and correlations of baryonic chiral partners, Phys. Rev. D 109, 014033 (2024), arXiv:2308.15794 [hep- ph]

  60. [61]

    Probing nuclear liquid-gas phase transition with isospin correlations

    M. Marczenko, K. Redlich, and C. Sasaki, Prob- ing the nuclear liquid-gas phase transition with isospin correlations, Phys. Rev. C 111, 065203 (2025), arXiv:2410.21746 [nucl-th]

  61. [62]

    Quarkyonic matter with chiral symmetry restoration

    B. Gao and M. Harada, Quarkyonic matter with chiral symmetry restoration, Phys. Rev. D 111, 016024 (2025), arXiv:2410.16649 [nucl-th]

  62. [63]

    Motohiro, Y

    Y. Motohiro, Y. Kim, and M. Harada, Asymmetric nu- clear matter in a parity doublet model with hidden local symmetry, Phys. Rev. C 92, 025201 (2015)

  63. [64]

    Zhao and J

    T. Zhao and J. M. Lattimer, Quarkyonic Matter Equa- tion of State in Beta-Equilibrium, Phys. Rev. D 102, 023021 (2020), arXiv:2004.08293 [astro-ph.HE]

This paper was first reviewed by deepseek-v4-flash on August 5, 2026.