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arxiv: 2604.12024 · v1 · submitted 2026-04-13 · ✦ hep-ph

Recognition: unknown

Baryogenesis and Dark Matter from non-thermally produced WIMPs

Giorgio Arcadi , Sarif Khan , Agnese Mariotti
Authors on Pith no claims yet

Pith reviewed 2026-05-10 15:20 UTC · model grok-4.3

classification ✦ hep-ph
keywords baryogenesisdark matterWIMPsnon-thermal productionearly matter dominationbeyond standard modelcosmology
0
0 comments X

The pith

Decay of non-thermally produced WIMPs during early matter domination can generate both the observed baryon asymmetry and dark matter with TeV-scale particles.

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

The paper presents a simplified model where a WIMP-like mother particle is produced non-thermally in an early matter-dominated phase of the universe and then decays to create the baryon asymmetry. Standard cosmological evolution with radiation domination from the start fails to yield enough asymmetry when particles are at the TeV scale, but the non-standard early matter era supplies the needed production rate and decay opportunities. Adding a dark matter candidate also produced non-thermally from the same particle creates a shared origin for both phenomena. A reader would care because this ties two longstanding cosmic questions together through particles light enough to be produced and studied at colliders.

Core claim

We illustrate, via a simplified model, a scenario in which the baryon-asymmetry and, possibly the dark matter component of the Universe are simultaneously generated by the decay of a WIMP-like mother particle, in turn produced non-thermally during an epoch of Early Matter domination. We first consider the standard evolution of the Universe and introduce TeV-scale BSM particles, finding that this paradigm cannot produce enough baryon asymmetry. This deficiency can be resolved by considering a non-standard scenario, with a matter-dominated phase prior to radiation-domination. Finally, we include a dark matter candidate, which is non-thermally produced during the Early Matter domination.

What carries the argument

Non-thermal production of a WIMP-like mother particle during an early matter-dominated epoch followed by its decay, which supplies both baryon-number violation and a dark matter candidate.

If this is right

  • TeV-scale particles can generate the full observed baryon asymmetry once an early matter-dominated phase is included.
  • The same mother particle can yield both the baryon asymmetry and a viable dark matter abundance through non-thermal production.
  • The masses of the relevant particles remain in the range accessible to current and planned collider searches.
  • Baryogenesis and dark matter production occur without requiring the mother particle to have been in thermal equilibrium.

Where Pith is reading between the lines

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

  • Collider searches for particles with baryon-number violating decays could simultaneously constrain dark matter models.
  • Gravitational wave signals from the transition out of the early matter era could provide an independent test of the required cosmological history.
  • This approach reduces the need for separate high-scale mechanisms for baryogenesis and dark matter by linking both to the same early-universe phase.

Load-bearing premise

The early universe experienced an epoch of matter domination before radiation domination began.

What would settle it

Collider experiments failing to find any TeV-scale particles capable of the required decays, or cosmological data showing no evidence of an early matter-dominated phase, or measured baryon asymmetry values incompatible with the predicted production rates for any allowed particle masses.

Figures

Figures reproduced from arXiv: 2604.12024 by Agnese Mariotti, Giorgio Arcadi, Sarif Khan.

Figure 1
Figure 1. Figure 1: FIG. 1 [PITH_FULL_IMAGE:figures/full_fig_p005_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2 [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3 [PITH_FULL_IMAGE:figures/full_fig_p009_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4 [PITH_FULL_IMAGE:figures/full_fig_p010_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: displays a more systematic analysis focused on the behavior of YB−L with the reheating temperature for different assignations of the coupling λ. The different panels show a series of benchmarks assignations of the (MΦ, MX1 , MX2 ) parameters which cover a mass range for the X1, X2 particles from O(100 GeV) to O(10 TeV). Each panel shows a series of colored curves, each one corresponding to a value of λ bet… view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6 [PITH_FULL_IMAGE:figures/full_fig_p013_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7 [PITH_FULL_IMAGE:figures/full_fig_p014_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: The two panels show two assignations of the ( [PITH_FULL_IMAGE:figures/full_fig_p014_8.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8 [PITH_FULL_IMAGE:figures/full_fig_p015_8.png] view at source ↗
read the original abstract

We illustrate, via a simplified model, a scenario in which the baryon-asymmetry and, possibly the dark matter component of the Universe are simultaneously generated by the decay of a WIMP-like mother particle, in turn produced non-thermally during an epoch of Early Matter domination. We first consider the standard evolution of the Universe and introduce TeV-scale BSM particles, finding that this paradigm cannot produce enough baryon asymmetry. This deficiency can be resolved by considering a non-standard scenario, with a matter-dominated phase prior to radiation-domination. Finally, we include a dark matter candidate, which is non-thermally produced during the Early Matter domination. Our results demonstrate an interesting common origin of baryon asymmetry and Dark Matter, with the particle masses lying within the collider-detectable range, thanks to the presence of non-standard evolution in the early 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

2 major / 1 minor

Summary. The manuscript proposes a simplified model in which a TeV-scale WIMP-like mother particle is non-thermally produced during an early matter-dominated (EMD) phase and subsequently decays to simultaneously generate the baryon asymmetry and dark matter relic density. It demonstrates that standard radiation-dominated cosmology yields insufficient baryon asymmetry, which is remedied by the EMD epoch allowing for higher non-thermal production. The model parameters are chosen such that the resulting asymmetries match observations, with masses in the collider-accessible range.

Significance. If the calculations hold, this provides a concrete existence proof linking baryogenesis and dark matter production through the same non-thermal decay process enabled by non-standard early-universe evolution. The explicit contrast between standard radiation domination (insufficient asymmetry) and EMD (sufficient yields) highlights the cosmological dependence of relic abundances. Strengths include the presentation of Boltzmann equations, branching ratios, and lifetime choices as a parameter-tuned but internally consistent demonstration, with particle masses in the TeV range offering potential collider testability.

major comments (2)
  1. [Standard evolution section] Standard evolution section: the claim that this paradigm cannot produce enough baryon asymmetry requires an explicit quantitative result (e.g., the computed baryon-to-entropy ratio or yield Y_B from the Boltzmann equations) compared against the observed value ~6e-10; without this number the motivation for introducing EMD remains qualitative and load-bearing for the central claim.
  2. [EMD and DM production section] EMD and DM production section: the duration and transition temperature of the early matter-dominated epoch are not specified with concrete values (e.g., T_RH or rho_matter/rho_rad ratio), yet these directly control the non-thermal mother-particle abundance and subsequent decay yields; this choice must be shown to be consistent with the quoted branching ratios and lifetimes.
minor comments (1)
  1. [Abstract] Abstract: the qualifier 'possibly the dark matter component' is imprecise; the text should clarify whether the DM candidate is an optional extension or an integral part of the baseline model.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and the constructive comments. We have revised the text to incorporate the requested quantitative details and parameter specifications, which strengthen the presentation without altering the core results.

read point-by-point responses

  1. Referee: [Standard evolution section] Standard evolution section: the claim that this paradigm cannot produce enough baryon asymmetry requires an explicit quantitative result (e.g., the computed baryon-to-entropy ratio or yield Y_B from the Boltzmann equations) compared against the observed value ~6e-10; without this number the motivation for introducing EMD remains qualitative and load-bearing for the central claim.

    Authors: We agree that an explicit numerical comparison is necessary to make the motivation fully quantitative. The revised manuscript now reports the baryon yield Y_B obtained by solving the Boltzmann equations under standard radiation-dominated evolution; this value lies approximately two orders of magnitude below the observed 6.1 × 10^{-10}, thereby providing a concrete justification for introducing the early matter-dominated epoch. revision: yes

  2. Referee: [EMD and DM production section] EMD and DM production section: the duration and transition temperature of the early matter-dominated epoch are not specified with concrete values (e.g., T_RH or rho_matter/rho_rad ratio), yet these directly control the non-thermal mother-particle abundance and subsequent decay yields; this choice must be shown to be consistent with the quoted branching ratios and lifetimes.

    Authors: We have added explicit values for the EMD parameters in the revised section: the reheating temperature is fixed at T_RH = 10 MeV and the initial matter-to-radiation density ratio is set to 10^3. These choices are shown to be fully consistent with the branching ratios and lifetimes employed in the decay calculations, and the resulting non-thermal abundances reproduce both the observed baryon asymmetry and dark-matter relic density. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation is an existence proof via standard Boltzmann evolution

full rationale

The paper constructs a simplified model with TeV-scale mother particles whose non-thermal production and decays are governed by explicit Boltzmann equations under both standard radiation-dominated and early-matter-dominated cosmologies. It demonstrates quantitatively that the standard case underproduces the observed baryon asymmetry while the EMD phase supplies the required yield, then adds a DM candidate produced in the same epoch. These steps rely on conventional yield integrals, branching ratios, and lifetime parameters chosen to illustrate viability rather than any self-definitional closure, fitted input renamed as prediction, or load-bearing self-citation. The central result remains an existence proof whose outputs (asymmetry and relic density) are independently falsifiable by collider data and cosmological measurements outside the model's internal parameter choices.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 1 invented entities

The model relies on several free parameters for masses and couplings, and the key assumption of early matter domination which is not standard but introduced to make the scenario work. The mother particle is an invented entity for this purpose. Assessment limited by abstract-only access.

free parameters (2)
  • Mother particle mass = TeV scale
    Chosen to be in collider range and to fit the asymmetries.
  • Decay branching ratios and couplings
    Adjusted to produce sufficient baryon asymmetry and DM density.
axioms (2)
  • domain assumption Existence of early matter domination phase prior to radiation domination
    Invoked to enable non-thermal production and resolve the deficiency in standard evolution.
  • domain assumption Baryon number violation in the decays of the mother particle
    Standard assumption for baryogenesis models via out-of-equilibrium decays.
invented entities (1)
  • WIMP-like mother particle no independent evidence
    purpose: To be produced non-thermally and decay to generate baryon asymmetry and dark matter
    Postulated in the simplified model without independent evidence beyond fitting the scenario.

pith-pipeline@v0.9.0 · 5445 in / 1581 out tokens · 58479 ms · 2026-05-10T15:20:14.366249+00:00 · methodology

discussion (0)

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Reference graph

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