Connecting Flavor and Baryon Asymmetry via Leptogenesis in Effective Froggatt-Nielsen Theory

Cheshta Batra; Kunal Rawat; Rusa Mandal; Tom Tong

REVIEW 3 major objections 2 minor 1 cited by

One Froggatt-Nielsen scale can make dark matter and the baryon asymmetry together while fitting flavor hierarchies.

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 →

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T0 review · grok-4.5

2026-07-15 14:36 UTC pith:5AKOPTAF

load-bearing objection Abstract-only dual-regime leptogenesis claim in an FN+RHN setup; interesting unification idea, but nothing numerical is checkable yet. the 3 major comments →

arxiv 2603.05372 v2 pith:5AKOPTAF submitted 2026-03-05 hep-ph hep-ex

Connecting Flavor and Baryon Asymmetry via Leptogenesis in Effective Froggatt-Nielsen Theory

Cheshta Batra , Rusa Mandal , Kunal Rawat , Tom Tong This is my paper

classification hep-ph hep-ex PACS 12.60.-i14.60.Pq98.80.Cq95.35.+d

keywords Froggatt-Nielsenleptogenesisbaryon asymmetryright-handed neutrinosType-I seesawflavonfreeze-infreeze-out

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.

This paper claims that a single Froggatt-Nielsen effective theory, with one complex flavon that breaks a U(1) flavor symmetry, can simultaneously produce the observed fermion mass hierarchies and mixings, light neutrino masses via a Type-I seesaw with three right-handed neutrinos, a viable dark-matter candidate (the lightest right-handed neutrino), and the observed baryon asymmetry of the Universe through thermal leptogenesis. The same symmetry-breaking scale that sets the right-handed-neutrino masses also sets the interaction strengths of the flavon and dark-matter sectors, so the two known production regimes for that dark-matter candidate—freeze-in at large scale and freeze-out at small scale—both remain compatible with successful leptogenesis. In the large-scale regime the calculation recovers ordinary thermal leptogenesis; in the small-scale regime the lighter right-handed neutrinos require resonant enhancement of the CP asymmetry, which the authors show can still work once flavon-induced scatterings are included in the Boltzmann equations. If correct, the construction supplies a tightly constrained, predictive link among flavor, neutrinos, dark matter, and baryogenesis inside one effective Lagrangian.

Core claim

Successful thermal leptogenesis is possible in both the large-v_φ (freeze-in) and small-v_φ (freeze-out) regimes of a single Froggatt-Nielsen theory in which the flavon vacuum expectation value simultaneously controls right-handed-neutrino masses and the interaction strengths of the flavon and dark-matter sectors.

What carries the argument

The complex flavon field φ whose vacuum expectation value v_φ breaks U(1)_FN and generates hierarchical Yukawa couplings through higher-dimensional operators; the same v_φ sets the right-handed-neutrino mass matrix that sources both the Type-I seesaw and the out-of-equilibrium decays that produce the lepton asymmetry.

Load-bearing premise

That the same Froggatt-Nielsen charge assignments and complex coefficients that fit CKM and PMNS data also keep the lightest right-handed neutrino a viable dark-matter candidate while still generating enough CP asymmetry for leptogenesis, especially under resonant conditions at low v_φ.

What would settle it

A combined numerical scan that enforces simultaneous reproduction of measured CKM/PMNS parameters, the observed dark-matter relic density via freeze-in or freeze-out, and a baryon asymmetry Y_B ≈ 8.7 × 10^{-11} would return an empty parameter space in one or both of the v_φ regimes.

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

If this is right

Flavor, neutrino masses, CP violation, dark matter, and baryogenesis are controlled by one continuous parameter v_φ inside a single effective theory.
In the freeze-in-compatible (large-v_φ) window the leptogenesis calculation reduces to the standard thermal result.
In the freeze-out-compatible (small-v_φ) window lighter right-handed neutrinos still generate the observed baryon asymmetry once resonant enhancement and flavon-induced channels are included.
CP-violating phases needed for leptogenesis are the same complex Froggatt-Nielsen coefficients that already generate meson-decay CP violation and the PMNS matrix.
The framework remains predictive: future improvements in neutrino oscillation parameters or dark-matter direct-detection limits can rule out large regions of the allowed v_φ range.

Where Pith is reading between the lines

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

Because the same complex coefficients source both low-energy CP violation and the leptogenesis asymmetry, precision measurements of meson-decay CP phases could indirectly constrain the high-scale CP sources required for baryogenesis.
The necessity of resonant leptogenesis at low v_φ suggests that a mild quasi-degeneracy among the two heavier right-handed neutrinos may be a generic, testable prediction of freeze-out-compatible Froggatt-Nielsen models.
If flavon-induced scatterings prove numerically important, similar initial-state scalar channels may need to be re-examined in other flavored leptogenesis scenarios that have so far omitted them.
A natural next check is whether the same charge assignments remain compatible with successful leptogenesis once renormalization-group running of the Yukawa couplings from the flavon scale down to the electroweak scale is included.

Editorial analysis

A structured set of objections, weighed in public.

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

Desk Editor's Note

Abstract-only dual-regime leptogenesis claim in an FN+RHN setup; interesting unification idea, but nothing numerical is checkable yet.

read the letter

The one thing to know: this abstract claims that a single Froggatt-Nielsen charge assignment plus one continuous scale v_φ can simultaneously fit flavor (CKM/PMNS), keep the lightest RHN as freeze-in or freeze-out DM, and produce the observed baryon asymmetry via thermal leptogenesis in both regimes, once flavon-initiated scatterings and resonant enhancement are included. That dual-regime statement is the actual new claim relative to the usual separate pieces of the literature.

What they do well on paper is the packaging. FN flavor + Type-I seesaw + RHN DM is not new, but folding flavon-initiated processes into the CP asymmetries and Boltzmann equations, and insisting that the same v_φ that sets RHN masses also sets the DM production window, is a clean organizing idea. Complex FN coefficients for CP phases and meson-decay signatures are a sensible extension of their prior work. If the numerics later hold, it is a useful single-scale BSM story for people who already live in this corner of phenomenology.

The soft spots are mostly information gaps, not proven contradictions. We have no charge tables, no CP-asymmetry formulae, no Boltzmann solutions, no scan plots, and no demonstration that resonant enhancement at low v_φ preserves the flavor fit without overproducing washout. The free parameters (complex coefficients, v_φ, mass splittings) are exactly the ones that usually get dialed to make leptogenesis work, so the “predictive” claim is still an assertion. Circularity risk is real but not yet fatal: the same knobs that fit flavor and DM may also be setting the asymmetry. The stress-test is right that the load-bearing premise is imported from prior work and not re-derived here; that is an abstract-only limitation, not an internal inconsistency.

Who it is for: model-builders and early-universe people who already care about FN + leptogenesis + RHN DM. Not a must-read for the broader community until the equations and scans appear. It deserves a serious referee if the full paper ships the Boltzmann machinery and the dual-regime plots; desk-rejecting an abstract-only claim would be premature. I would not cite it yet and would only bring it to reading group once the full text is out. Send it to peer review when the manuscript is complete; the idea is coherent enough to earn that time.

Referee Report

3 major / 2 minor

Summary. The manuscript studies an effective Froggatt–Nielsen (FN) framework in which a complex flavon spontaneously breaks a U(1)_FN symmetry and generates SM fermion masses and mixings via higher-dimensional operators. Three right-handed neutrinos (RHNs) implement Type-I seesaw neutrino masses; complex FN coefficients are used to accommodate the CKM and PMNS matrices and to induce CP-violating signatures. Building on prior work in which the lightest RHN is a dark-matter candidate produced by freeze-in or freeze-out, the authors investigate thermal leptogenesis from the heavier RHNs, including SM channels and flavon-initiated processes. They report one-loop CP asymmetries and their inclusion in Boltzmann equations, and claim that successful leptogenesis is achieved both in the large-v_φ (freeze-in-compatible) regime, approaching standard leptogenesis, and in the small-v_φ (freeze-out-compatible) regime, where resonant enhancement is required. The single continuous parameter v_φ is argued to control RHN masses and the interaction strengths of the flavon and DM sectors, yielding a unified description of flavor, neutrinos, CP violation, DM, and baryogenesis.

Significance. If the dual-regime leptogenesis results hold under a single set of FN charges and complex coefficients that also fit flavor data and preserve a viable lightest-RHN DM candidate, the work would provide a tightly constrained, predictive link among several open problems in particle physics and cosmology. Explicit inclusion of flavon-initiated channels and the mapping of freeze-in versus freeze-out onto distinct ranges of v_φ would be useful contributions to the FN-plus-leptogenesis literature. Because only the abstract is available for this review, the significance assessment remains conditional on verification of the numerical and analytic results that the abstract asserts.

major comments (3)

[Abstract (central numerical claim)] The abstract asserts that successful thermal leptogenesis is achieved in both the large-v_φ (freeze-in) and small-v_φ (freeze-out/resonant) regimes after computing one-loop CP asymmetries and solving Boltzmann equations that include flavon-initiated channels. With only the abstract available, none of the load-bearing ingredients—CP-asymmetry formulae, Boltzmann solutions, parameter scans, washout estimates, or error bars—can be inspected. The dual-regime success is therefore asserted rather than demonstrated in the material under review, and a technical assessment of the central claim is not possible.
[Abstract (FN charges and complex coefficients)] The framework relies on a single set of FN charge assignments and complex coefficients that must simultaneously (i) reproduce CKM/PMNS data, (ii) keep the lightest RHN a viable freeze-in or freeze-out DM candidate, and (iii) generate a sufficient lepton asymmetry that survives washout, with resonant enhancement required at low v_φ. The abstract does not show that the baryon asymmetry is an independent prediction rather than a quantity adjusted by the same free complex coefficients and by the RHN mass splittings that enable resonance. Without charge tables, fit-quality metrics, or a demonstration that resonance does not spoil the flavor fit or overproduce washout, this multi-purpose use of the same parameters remains a load-bearing assumption imported from prior work.
[Abstract (resonant regime at small v_φ)] In the freeze-out-compatible (small-v_φ) region the abstract states that lighter RHNs require resonant enhancement. Resonant leptogenesis is sensitive to mass splittings, CP phases, and washout; the abstract does not indicate how the required quasi-degeneracy is realized within the FN charge structure, nor whether the same complex coefficients that fit PMNS/CKM leave enough freedom for the necessary resonance without conflicting with flavor constraints. This point is essential to the claim that both regimes work inside one effective theory.

minor comments (2)

[Abstract] The abstract refers to “our previous work” for the lightest-RHN DM construction but does not identify that work by arXiv or journal reference in the abstract text provided; a self-contained abstract should cite it explicitly.
[Abstract] Notation for the FN-breaking scale is given as v_φ; it would help to state briefly whether the flavon remains complex after breaking and how the phase of ⟨φ⟩ is fixed or absorbed, given that complex FN coefficients are already used as the source of CP violation.

Circularity Check

0 steps flagged

Abstract-only review: no inspectable derivation chain; dual-regime claim is asserted, not shown to be circular by construction.

full rationale

Only the abstract is available, so no equations, charge tables, CP-asymmetry formulae, Boltzmann solutions, or numerical scans can be inspected. Circularity requires quoting a specific reduction (Eq. X = Eq. Y by construction, or a fitted parameter renamed as prediction). The abstract states that complex FN coefficients are chosen to describe CKM/PMNS, that the lightest RHN is a DM candidate from prior work, and that successful thermal leptogenesis is achieved in both large-v_φ and small-v_φ regimes, with resonant enhancement needed at low v_φ. These are modeling choices and claims of numerical success, not demonstrated self-definitional identities or fitted-input-as-prediction steps. Dependence on the authors’ previous DM paper is ordinary sequential research; without the prior paper or the present body, one cannot exhibit a load-bearing self-citation that forces the baryon asymmetry by construction. The dual-regime success may be under-constrained or tuned in the full paper, but that is a correctness/information-gap concern, not circularity under the stated rules. Honest non-finding: score 0, empty steps.

Axiom & Free-Parameter Ledger

3 free parameters · 4 axioms · 2 invented entities

The framework rests on standard FN and seesaw assumptions plus complex coefficients and a single scale v_φ that must simultaneously fit flavor data, DM abundance, and the baryon asymmetry. Free parameters are the FN charges/coefficients and v_φ (and any resonant mass splittings). No new particles beyond the usual flavon and three RHNs are invented; the main risk is that the same fitted inputs are asked to do too many jobs.

free parameters (3)

complex FN coefficients
Chosen so that higher-dimensional operators reproduce CKM and PMNS matrices and induce meson CP violation; they also enter the CP asymmetries for leptogenesis.
flavon VEV v_φ
Single scale that sets RHN masses, flavon interaction strengths, and which DM production regime (freeze-in vs freeze-out) is realized; scanned to achieve both DM and baryon asymmetry.
RHN mass splittings (resonant regime)
At low v_φ the abstract states resonant enhancement is required; the size of the mass splitting that produces the needed CP asymmetry is an additional tuned parameter.

axioms (4)

domain assumption U(1)_FN spontaneously broken by a complex flavon generates hierarchical fermion masses via higher-dimensional operators
Standard Froggatt-Nielsen premise; not derived here.
domain assumption Type-I seesaw with three right-handed neutrinos generates light neutrino masses
Standard seesaw assumption used to link RHN sector to light neutrinos.
ad hoc to paper Lightest RHN is a viable DM candidate via freeze-in or freeze-out (imported from authors’ previous work)
Abstract explicitly builds on prior result rather than re-establishing DM viability under the same charge assignments used for leptogenesis.
domain assumption Out-of-equilibrium decays and scatterings of heavier RHNs (including flavon-initiated channels) source a lepton asymmetry converted by sphalerons
Standard thermal leptogenesis plus the paper’s extension to flavon channels.

invented entities (2)

complex flavon field φ with U(1)_FN charge no independent evidence
purpose: Breaks FN symmetry and generates hierarchical Yukawas and RHN masses
Standard FN ingredient; independent evidence would be flavon-mediated rare processes or collider signals, not provided in the abstract.
three right-handed neutrinos (lightest as DM) no independent evidence
purpose: Seesaw masses, leptogenesis CP asymmetry, and dark-matter candidate
Standard BSM addition; viability as DM is taken from prior work and not independently demonstrated here.

pith-pipeline@v1.1.0-grok45 · 6253 in / 3298 out tokens · 31484 ms · 2026-07-15T14:36:25.005595+00:00 · methodology

0 comments

read the original abstract

We investigate the hierarchical flavor structure of the Standard Model (SM) in a Froggatt-Nielsen (FN) framework, where the spontaneous breaking of a $U(1)_{\rm FN}$ symmetry by a complex flavon field generates fermion masses and mixing patterns through higher-dimensional operators. Extending the setup with three right-handed neutrinos (RHNs), light neutrino masses arise via the Type-I seesaw mechanism. Allowing complex FN coefficients enables a consistent description of the CKM and PMNS matrices while inducing CP-violating signatures in meson decays. Building on our previous work, where the lightest RHN acts as a viable dark matter (DM) candidate produced through freeze-in or freeze-out mechanisms, we investigate the origin of the baryon asymmetry of the Universe. The heavier RHNs generate a lepton asymmetry through out-of-equilibrium decays and scatterings, including both SM channels and additional flavon-induced processes in which the flavon appears as an initial-state particle. We compute the corresponding one-loop CP asymmetries and incorporate these effects in the Boltzmann equations. We show that although freeze-in and freeze-out DM production occur in two qualitatively distinct regions of the FN symmetry-breaking scale $v_\phi$, successful thermal leptogenesis can be achieved in both regimes. In the large-$v_\phi$ (freeze-in-compatible) region, the results approach the standard leptogenesis limit, while in the freeze-out-compatible region the lower value of $v_\phi$ implies lighter RHNs, requiring resonant enhancement. This tightly constrained framework, in which $v_\phi$ simultaneously controls RHN masses and the interaction strengths of the flavon and DM sectors, provides a predictive and unified description of flavor hierarchies, neutrino masses, CP violation, DM, and baryogenesis within a single effective theory.

discussion (0)

Forward citations

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