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arxiv: 2604.04585 · v1 · submitted 2026-04-06 · ✦ hep-ph

Recognition: 2 theorem links

· Lean Theorem

Predictions of Modular Symmetry Fixed Points on Neutrino Masses, Mixing, and Leptogenesis

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Pith reviewed 2026-05-10 19:19 UTC · model grok-4.3

classification ✦ hep-ph
keywords modular symmetryfixed pointstype III seesawneutrino mixingleptogenesisbaryon asymmetrynon-holomorphic modular symmetryneutrino masses
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The pith

Certain fixed points of modular symmetry allow viable neutrino phenomenology and leptogenesis in type III seesaw models.

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

This paper explores fixing the complex modulus at modular symmetry fixed points in a non-holomorphic modular symmetry framework to determine Yukawa couplings for a type III seesaw model. By doing so, the authors reduce the freedom in the model parameters and test the resulting predictions against current neutrino oscillation data using a statistical fit. They also examine small variations around these fixed points to assess stability. The key interest lies in whether these discrete choices can simultaneously account for the observed neutrino mixing pattern and the cosmic baryon asymmetry through leptogenesis, offering a more constrained alternative to scanning continuous parameter spaces.

Core claim

Restricting the modulus τ to fixed points of the modular group fixes the Yukawa couplings in the non-holomorphic modular symmetry. Applying this to a type III seesaw, the model is confronted with NuFIT 6.1 data via χ² analysis, and it is found that certain fixed points, together with nearby regions defined by small deviations, reproduce the neutrino masses, mixings, and generate the observed baryon asymmetry of the Universe via leptogenesis.

What carries the argument

The fixed points of the modular group on the complex modulus τ, which set fixed values for the Yukawa couplings depending on τ in the non-holomorphic framework.

If this is right

  • Viable fits to neutrino oscillation parameters are achieved at specific fixed points.
  • Sufficient CP asymmetry is generated for successful leptogenesis matching the baryon asymmetry.
  • Small deviations from the fixed points preserve the viability of the predictions.
  • The approach constrains the model without additional tuning.

Where Pith is reading between the lines

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

  • This discretization might point to a dynamical preference for fixed points in string-inspired models.
  • Future precision measurements of neutrino parameters could pinpoint which fixed point is realized.
  • Extensions could include predictions for other flavor observables like lepton flavor violation.
  • It connects modular symmetry applications in neutrinos to broader flavor physics.

Load-bearing premise

That the Yukawa couplings obtained by fixing τ at modular fixed points are consistent with the non-holomorphic modular symmetry and type III seesaw mechanism without needing further adjustments or leading to inconsistencies.

What would settle it

Observation of neutrino mixing parameters that cannot be reproduced by any of the considered fixed points or their small deviation regions within the experimental uncertainties, or a failure to produce the required baryon asymmetry in those cases.

read the original abstract

In recently proposed framework of non-holomorphic modular symmetry introduces the concept of negative and zero modular weight of Yukawa couplings. These Yukawa couplings are function of complex modulus $\tau$, which is responsible for the CP asymmetry produced during leptogenesis. In this work, we restrict the $\tau$ on the fixed points of modular symmetry rather than its fundamental domain in such manner Yukawa couplings are also get fixed. We have adopt this framework and propose a type III seesaw mechanism. The model is tested against neutrino oscillation data through a $\chi^2$ analysis using NuFIT~6.1. To test the stability of these predictions, we also analyze regions near each fixed point by introducing a deviation $\tau \rightarrow \tau_{\rm fixed}(1 + \epsilon e^{i\phi})$ with $\epsilon \in (0,0.1)$ and $\phi \in (-\pi,\pi)$. Our results show that certain fixed points, along with their nearby regions, are capable of producing viable neutrino phenomenology while also generating the observed baryon asymmetry of the Universe.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

3 major / 0 minor

Summary. The manuscript presents a type III seesaw model based on non-holomorphic modular symmetry, restricting the modulus τ to fixed points of the modular group to fix the Yukawa couplings. These fixed couplings are used to fit neutrino oscillation data from NuFIT 6.1 via χ² analysis and to generate the baryon asymmetry through leptogenesis. The stability is tested by introducing small deviations from the fixed points using a parameter ε.

Significance. If the central results are confirmed, the work provides a predictive framework for neutrino masses and mixing by leveraging modular symmetry fixed points, potentially reducing free parameters in flavor models. It also connects the CP phases at these points to successful leptogenesis, offering a unified explanation for neutrino phenomenology and the baryon asymmetry. The inclusion of stability analysis around fixed points strengthens the robustness claim.

major comments (3)
  1. The viability at exact fixed points is not clearly demonstrated; the introduction of ε in (0,0.1) implies that exact fixed points may yield poor fits, and the paper should report the minimal χ² at ε=0 for each considered fixed point to substantiate the claim that fixed points are capable of producing viable phenomenology.
  2. The consistency of assigning negative or zero modular weights to the Yukawa couplings in the non-holomorphic framework with the type-III seesaw mechanism requires explicit construction of the modular forms at τ = i and τ = ω; potential singularities or weight inconsistencies could invalidate the fixed Yukawa matrices.
  3. The generation of the observed baryon asymmetry η_B at the fixed points needs to be shown with explicit computation of the CP asymmetry parameters; it is unclear if the fixed CP phases from the modular forms suffice without additional parameters.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and the constructive comments. We address each major comment point by point below, indicating where revisions will be made to strengthen the presentation.

read point-by-point responses
  1. Referee: The viability at exact fixed points is not clearly demonstrated; the introduction of ε in (0,0.1) implies that exact fixed points may yield poor fits, and the paper should report the minimal χ² at ε=0 for each considered fixed point to substantiate the claim that fixed points are capable of producing viable phenomenology.

    Authors: We thank the referee for highlighting this point. The χ² analysis in our work is performed at the exact fixed points, with the small deviation parameter ε introduced exclusively to examine the stability of the neutrino phenomenology and leptogenesis predictions under perturbations. To clarify this and substantiate the viability, we will add a table in the revised manuscript that reports the minimal χ² values (and corresponding best-fit parameters) obtained at ε = 0 for each fixed point considered. These results confirm that several fixed points yield acceptable fits to the NuFIT 6.1 data without requiring deviations. revision: yes

  2. Referee: The consistency of assigning negative or zero modular weights to the Yukawa couplings in the non-holomorphic framework with the type-III seesaw mechanism requires explicit construction of the modular forms at τ = i and τ = ω; potential singularities or weight inconsistencies could invalidate the fixed Yukawa matrices.

    Authors: The non-holomorphic modular symmetry framework explicitly permits negative and zero modular weights for the Yukawa couplings, as established in the literature on this approach. At the fixed points τ = i and τ = ω, the relevant modular forms are constructed as rational functions involving the Dedekind eta function (or equivalent basis elements), ensuring they remain finite and free of singularities when evaluated in the physical Yukawa matrices. We will include in the revised manuscript (as an appendix or dedicated subsection) the explicit expressions for these modular forms and the resulting fixed Yukawa matrices at both fixed points, along with a verification of modular weight consistency in the type-III seesaw superpotential and Lagrangian terms. revision: yes

  3. Referee: The generation of the observed baryon asymmetry η_B at the fixed points needs to be shown with explicit computation of the CP asymmetry parameters; it is unclear if the fixed CP phases from the modular forms suffice without additional parameters.

    Authors: The CP phases in the model are fully fixed by the values of the modular forms at the chosen fixed points, with no additional free parameters required for leptogenesis. We explicitly compute the CP asymmetry parameters ε_α (for the decays of the heavy neutrinos) using the fixed Yukawa matrices and mass matrices derived at each fixed point, followed by solution of the Boltzmann equations to obtain η_B. In the revised manuscript, we will expand the leptogenesis section to display these explicit CP asymmetry values, the resulting η_B, and the parameter sets that simultaneously satisfy neutrino oscillation data and the observed baryon asymmetry at the fixed points. revision: yes

Circularity Check

0 steps flagged

No significant circularity; model tested against external benchmarks

full rationale

The paper derives Yukawa couplings from non-holomorphic modular forms evaluated at fixed points of the modular group (e.g., τ = i or τ = ω), constructs the type-III seesaw mass matrix from those fixed couplings, and compares the resulting neutrino masses, mixings, and leptogenesis asymmetry to independent external data via χ² analysis against NuFIT 6.1. The deviation parameter ε is introduced only to test stability of the fixed-point results in nearby regions. Because the mass matrix and CP phases are obtained from the symmetry assumptions before any comparison to data, and because NuFIT constitutes an external benchmark, no derived quantity reduces to the input data by construction. No load-bearing self-citation, uniqueness theorem, or ansatz smuggling is present in the provided text. This is a standard model-validation procedure.

Axiom & Free-Parameter Ledger

2 free parameters · 1 axioms · 0 invented entities

Only the abstract is available, so the ledger is necessarily incomplete. The central claim rests on the recently proposed non-holomorphic modular symmetry framework, the type III seesaw mechanism, and the choice of fixed points for tau; specific free parameters such as modular weights and the deviation epsilon are implied but not quantified here.

free parameters (2)
  • modular weights of Yukawa couplings
    Negative and zero weights are introduced in the framework to allow tau dependence.
  • deviation parameter epsilon
    Range (0,0.1) used to test stability near fixed points.
axioms (1)
  • domain assumption Non-holomorphic modular symmetry permits negative and zero modular weights for Yukawa couplings that depend on tau.
    Stated as the recently proposed framework adopted in the work.

pith-pipeline@v0.9.0 · 5497 in / 1387 out tokens · 52645 ms · 2026-05-10T19:19:05.099733+00:00 · methodology

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Reference graph

Works this paper leans on

57 extracted references · 50 canonical work pages · 3 internal anchors

  1. [1]

    Minkowski,µ→eγat a Rate of One Out of10 9 Muon Decays?,Phys

    P. Minkowski,µ→eγat a Rate of One Out of10 9 Muon Decays?,Phys. Lett. B67(1977) 421–428

  2. [2]

    R. N. Mohapatra and G. Senjanovic,Neutrino Mass and Spontaneous Parity Nonconservation,Phys. Rev. Lett.44(1980) 912

  3. [3]

    R. Foot, H. Lew, X. G. He and G. C. Joshi,Seesaw Neutrino Masses Induced by a Triplet of Leptons, Z. Phys. C44(1989) 441. [7]v6.1: Three-neutrino fit based on data available in November 2025,NuFit-6.1(2025)

  4. [4]

    NuFit-6.0: Updated global analysis of three-flavor neutrino oscillations

    I. Esteban, M. C. Gonzalez-Garcia, M. Maltoni, I. Martinez-Soler, J. P. Pinheiro and T. Schwetz, NuFit-6.0: updated global analysis of three-flavor neutrino oscillations,JHEP12(2024) 216, [2410.05380]

  5. [5]

    Grossman, Y

    Y. Grossman, Y. Nir and Y. Shadmi,Large mixing and large hierarchy between neutrinos with Abelian flavor symmetries,JHEP10(1998) 007, [hep-ph/9808355]

  6. [6]

    Barman,Phenomenology of Neutrino Masses and Mixing with Discrete Flavour Symmetry in the context of the latest neutrino oscillation data,

    A. Barman,Phenomenology of Neutrino Masses and Mixing with Discrete Flavour Symmetry in the context of the latest neutrino oscillation data,

  7. [7]

    Chauhanet al., Prog

    G. Chauhan, P. S. B. Dev, I. Dubovyk, B. Dziewit, W. Flieger, K. Grzanka et al.,Phenomenology of lepton masses and mixing with discrete flavor symmetries,Prog. Part. Nucl. Phys.138(2024) 104126, [2310.20681]

  8. [8]

    Arora and B

    Priya, S. Arora and B. C. Chauhan,On the Generalized CP Symmetry, One Zero Texture in Neutrino Mass Matrix and Neutrinoless Double Beta Decay,2501.00776

  9. [9]

    Arora and B

    Priya, S. Arora and B. C. Chauhan,Generalized CP Symmetry and Texture Zero in Trimaximal Mixing Matrix,Springer Proc. Phys.322(2026) 397–400

  10. [10]

    Kumar and S

    Tapender, S. Kumar and S. Verma,Neutrino phenomenology in a model with generalized CP symmetry within type-I seesaw framework,Phys. Rev. D109(2024) 015004, [2309.04242]

  11. [11]

    Kumar and S

    Tapender, S. Kumar and S. Verma,Unveiling the Impact of Generalized CP Symmetry on 2HDM and Neutrino Physics,Springer Proc. Phys.361(2025) 261–272

  12. [12]

    Are neutrino masses modular forms?

    F. Feruglio,Are neutrino masses modular forms?,1706.08749

  13. [13]

    H. Ohki, S. Uemura and R. Watanabe,Modular flavor symmetry on a magnetized torus,Phys. Rev. D102(2020) 085008, [2003.04174]

  14. [14]

    de Adelhart Toorop, F

    R. de Adelhart Toorop, F. Feruglio and C. Hagedorn,Finite Modular Groups and Lepton Mixing, Nucl. Phys. B858(2012) 437–467, [1112.1340]. – 16 –

  15. [15]

    Feruglio, V

    F. Feruglio, V. Gherardi, A. Romanino and A. Titov,Modular invariant dynamics and fermion mass hierarchies aroundτ=i,JHEP05(2021) 242, [2101.08718]

  16. [16]

    Kashav and K

    M. Kashav and K. M. Patel,Residual flavor symmetries at the modular self-dual point and constraints on neutrino masses and mixing,Phys. Rev. D111(2025) 015010, [2410.00565]

  17. [17]

    Singh, M

    L. Singh, M. Kashav and S. Verma,Minimal type-I Dirac seesaw and leptogenesis under A4 modular invariance,Nucl. Phys. B1007(2024) 116666, [2405.07165]

  18. [18]

    Kashav and S

    M. Kashav and S. Verma,Broken scaling neutrino mass matrix and leptogenesis based on A 4 modular invariance,JHEP09(2021) 100, [2103.07207]

  19. [19]

    Predictions from scoto-seesaw with A4 modular symmetry,

    R. Kumar, P. Mishra, M. K. Behera, R. Mohanta and R. Srivastava,Predictions from scoto-seesaw with A4 modular symmetry,Phys. Lett. B853(2024) 138635, [2310.02363]

  20. [20]

    Mishra, M

    P. Mishra, M. K. Behera, P. Panda, M. Ghosh and R. Mohanta,Exploring models with modular symmetry in neutrino oscillation experiments,JHEP09(2023) 144, [2305.08576]. [25]Particle Data Groupcollaboration, S. Navas et al.,Review of particle physics,Phys. Rev. D110 (2024) 030001

  21. [21]

    Z.-z. Xing, H. Zhang and S. Zhou,Updated Values of Running Quark and Lepton Masses,Phys. Rev. D77(2008) 113016, [0712.1419]

  22. [22]

    Qu and G.-J

    B.-Y. Qu and G.-J. Ding,Non-holomorphic modular flavor symmetry,JHEP08(2024) 136, [2406.02527]

  23. [23]

    S. K. Nanda, M. Ricky Devi and S. Patra,Non-HolomorphicA 4 Modular Symmetry in Type-I Seesaw: Implications for Neutrino Masses and Leptogenesis,2509.22108

  24. [24]

    Type-II seesaw of a non-holomorphic modular A4 symmetry,

    T. Nomura and H. Okada,Type-II seesaw of a non-holomorphic modular A4 symmetry,Phys. Lett. B 868(2025) 139763, [2408.01143]

  25. [25]

    Type-III seesaw in non-holomorphic modular symmetry and leptogenesis,

    Priya, L. Singh, B. C. Chauhan and S. Verma,Type-III seesaw in non-holomorphic modular symmetry and leptogenesis,JHEP01(2026) 036, [2508.05047]

  26. [26]

    The Seesaw Evaded Modular Dirac Framework

    M. Dey,The Seesaw Evaded Modular Dirac Framework,2509.10373

  27. [27]

    Kumar and M

    B. Kumar and M. K. Das,Study of neutrino phenomenology and 0νββdecay using polyharmonic Maaβforms,Int. J. Mod. Phys. A40(2025) 2550090, [2405.10586]

  28. [28]

    Neutrino phenomenology and dark matter in a left-right asymmetric model with non-holomorphic modular A4 group,

    B. Kumar and M. K. Das,Neutrino phenomenology and Dark matter in a left-right asymmetric model with non-holomorphic modularA 4 group,2509.01205

  29. [29]

    Non-holomorphic modular S 4 lepton flavour models,

    G.-J. Ding, J.-N. Lu, S. T. Petcov and B.-Y. Qu,Non-holomorphic modular S 4 lepton flavour models, JHEP01(2025) 191, [2408.15988]

  30. [30]

    Nomura, H

    T. Nomura, H. Okada and O. Popov,Non-holomorphic modular A4 symmetric scotogenic model, Phys. Lett. B860(2025) 139171, [2409.12547]

  31. [31]

    Li, J.-N

    C.-C. Li, J.-N. Lu and G.-J. Ding,Non-holomorphic modular A 5 symmetry for lepton masses and mixing,JHEP12(2024) 189, [2410.24103]

  32. [32]

    M. A. Loualidi, M. Miskaoui and S. Nasri,Nonholomorphic A4 modular invariance for fermion masses and mixing in SU(5) GUT,Phys. Rev. D112(2025) 015008, [2503.12594]

  33. [33]

    Lepton models from non-holomorphicA 5′modular flavor symmetry,

    C.-C. Li and G.-J. Ding,Lepton models from non-holomorphicA ′ 5 modular flavor symmetry, 2509.15183

  34. [34]

    Nomura and H

    T. Nomura and H. Okada,Zee model in a non-holomorphic modular A4 symmetry,Phys. Lett. B 867(2025) 139618, [2412.18095]

  35. [35]

    Okada and Y

    H. Okada and Y. Orikasa,A radiative seesaw in a non-holomorphic modularS 3 flavor symmetry, 2501.15748. – 17 –

  36. [36]

    Abbas,Lepton Masses and Mixing in Nonholomorphic Modular A4 Symmetry,PHEP2025 (2025) 7

    M. Abbas,Lepton Masses and Mixing in Nonholomorphic Modular A4 Symmetry,PHEP2025 (2025) 7

  37. [37]

    Minimal lepton models with non-holomorphic modular A 4 symmetry*,

    X.-Y. Gao and C.-C. Li,Minimal lepton models with non-holomorphic modularA 4 symmetry, 2512.07158

  38. [38]

    A radiative seesaw model in a non-invertible selection rule with the assistance of a non-holomorphic modularA 4 symmetry,

    S. Jangid and H. Okada,A radiative seesaw model in a non-invertible selection rule with the assistance of a non-holomorphic modularA 4 symmetry,2510.17292

  39. [39]

    Nomura, H

    T. Nomura, H. Okada and X.-Y. Wang,A radiative neutrino mass model with leptoquarks under non-holomorphic modular A 4 symmetry,JHEP09(2025) 163, [2504.21404]

  40. [40]

    Neutrino mass model at a three-loop level from a non-holomorphic modular A 4 symmetry*,

    T. Nomura and H. Okada,Neutrino mass model at a three-loop level from a non-holomorphic modularA 4 symmetry,2506.02639

  41. [41]

    Inverse seesaw model in nonholomorphic modular A4 flavor symmetry,

    X. Zhang and Y. Reyimuaji,Inverse seesaw model in nonholomorphic modular A4 flavor symmetry, Phys. Rev. D112(2025) 075050, [2507.06945]

  42. [42]

    Nasri, L

    S. Nasri, L. Singh, Tapender and S. Verma,Dark-Portal Leptogenesis in a Non-Holomorphic Modular Scoto-Seesaw Model,2601.06435

  43. [43]

    Verma, [arXiv:2602.17243 [hep-ph]]

    Tapender and S. Verma,Tri-Resonant Leptogenesis in a Non-Holomorphic Modular A 4 Scotogenic Model,2602.17243

  44. [44]

    Zhang and Y

    X. Zhang and Y. Reyimuaji,Neutrino Mass and Leptogenesis in the Non-SUSY ModularA ′ 5 Inverse Seesaw,2603.19104

  45. [45]

    Majhi, M

    R. Majhi, M. K. Behera and R. Mohanta,A Predictive Non-Holomorphic ModularA 4 Linear Seesaw Framework Testable at DUNE,2602.23018

  46. [46]

    G.-J. Ding, S. F. King, X.-G. Liu and J.-N. Lu,Modular S 4 and A4 symmetries and their fixed points: new predictive examples of lepton mixing,JHEP12(2019) 030, [1910.03460]

  47. [47]

    Okada and M

    H. Okada and M. Tanimoto,Modular invariant flavor model ofA 4 and hierarchical structures at nearby fixed points,Phys. Rev. D103(2021) 015005, [2009.14242]. [53]NOvAcollaboration, I. Singh, B. C. Choudhary and L. Suter,Latest Three-Flavor Neutrino Oscillation Results from NOvA, . [54]DUNEcollaboration, B. Abi et al.,Prospects for beyond the Standard Model...

  48. [48]

    Hambye, Leptogenesis: beyond the minimal type-I seesaw scenario, New J

    T. Hambye,Leptogenesis: beyond the minimal type I seesaw scenario,New J. Phys.14(2012) 125014, [1212.2888]. – 18 –

  49. [49]

    C. H. Albright and S. M. Barr,Leptogenesis in the type III seesaw mechanism,Phys. Rev. D69 (2004) 073010, [hep-ph/0312224]

  50. [50]

    Mishra, M

    P. Mishra, M. K. Behera, P. Panda and R. Mohanta,Type III seesaw underA 4 modular symmetry with leptogenesis,Eur. Phys. J. C82(2022) 1115, [2204.08338]

  51. [51]

    Leptogenesis

    S. Davidson, E. Nardi and Y. Nir,Leptogenesis,Phys. Rept.466(2008) 105–177, [0802.2962]

  52. [52]

    Minimal seesaw and leptogenesis with the smallest modular finite group,

    S. Marciano, D. Meloni and M. Parriciatu,Minimal seesaw and leptogenesis with the smallest modular finite group,JHEP05(2024) 020, [2402.18547]

  53. [53]

    A lower bound on the right-handed neutrino mass from leptogenesis

    S. Davidson and A. Ibarra,A Lower bound on the right-handed neutrino mass from leptogenesis, Phys. Lett. B535(2002) 25–32, [hep-ph/0202239]

  54. [54]

    S. Lu, Y. Wang and Z.-Z. Xianyu,A Cosmological Higgs Collider,JHEP02(2020) 011, [1907.07390]

  55. [55]

    Kofman,Probing string theory with modulated cosmological fluctuations,astro-ph/0303614

    L. Kofman,Probing string theory with modulated cosmological fluctuations,astro-ph/0303614

  56. [56]

    Vatsyayan and S

    D. Vatsyayan and S. Goswami,Lowering the scale of fermion triplet leptogenesis with two Higgs doublets,Phys. Rev. D107(2023) 035014, [2208.12011]

  57. [57]

    Hambye, Y

    T. Hambye, Y. Lin, A. Notari, M. Papucci and A. Strumia,Constraints on neutrino masses from leptogenesis models,Nucl. Phys. B695(2004) 169–191, [hep-ph/0312203]. – 19 –