Pith. sign in

REVIEW 3 major objections 4 minor 67 references

Decoupled freeze-out keeps s-wave dark matter viable where the thermal secluded scenario is ruled out.

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 →

T0 review · deepseek-v4-flash

2026-08-03 21:33 UTC pith:ZXQBN32B

load-bearing objection Genuinely new s-wave DFO setup with a solid constraint map; the main soft spots are the unverified single-temperature assumption and the missing public code. the 3 major comments →

arxiv 2511.14635 v2 pith:ZXQBN32B submitted 2025-11-18 hep-ph

Probing the Phenomenology of Dark Matter from Decoupled Freeze-Out

classification hep-ph
keywords dark matterdecoupled freeze-outs-wave annihilationsecluded freeze-outrelic densityCMB constraintsindirect detectionbig bang nucleosynthesis
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.

After reheating, the dark sector starts empty; this paper argues that if the dark matter–mediator couplings are strong enough to thermalize the hidden sector among itself but the mediator–Standard Model couplings are feeble, the hidden sector reaches its own lower temperature T' and dark matter freezes out from this decoupled bath. In a model with a fermion dark matter candidate and a scalar plus pseudoscalar mediator, the dominant annihilation χχ→aφ is s-wave, so the coupling required to reproduce Ωh²≈0.12 is smaller than in the standard thermal story, which relaxes the CMB bound that otherwise excludes sub-10 GeV s-wave dark matter. The authors solve four coupled Boltzmann equations—three number densities and the hidden-sector energy density—and map the DFO-viable region for mediator masses 250 MeV, 3 GeV, and 30 GeV. They find that after CMB, indirect-detection, and BBN constraints are imposed, a viable region of couplings remains, whereas the comparable secluded freeze-out scenario is entirely excluded for light mediators. The result matters because it gives concrete, testable predictions for light dark matter that would otherwise be considered dead.

Core claim

The central discovery is that decoupled freeze-out works for s-wave annihilation in a two-mediator model, and that it is more viable than the secluded scenario. For each of three benchmark mediator masses (250 MeV, 3 GeV, 30 GeV), the paper maps a band in the (mχ, gχ) plane that yields the observed relic density, with mediator–SM couplings in the range 10⁻¹⁰ to 10⁻¹³ GeV⁻¹ and DM–mediator couplings in the range 10⁻³ to 10⁻² GeV⁻¹. The band is bounded above by the transition to secluded freeze-out (where the dark sector equilibrates with the SM) and below by insufficient energy transfer (where the dark sector never gets populated). Imposing CMB power-spectrum, gamma-ray, radio, and BBN constr

What carries the argument

The central object is the s-wave annihilation χχ→aφ, which keeps the hidden sector in chemical equilibrium at a dark temperature T'<T until freeze-out. Because the annihilation rate scales as ⟨σv⟩ ∝ (g_aχ g_φχ)² and the required coupling for a given relic density is smaller at the lower T', the mechanism evades CMB constraints. The system is described by four coupled Boltzmann equations: three for the number densities of χ, a, φ and one for the hidden-sector energy density ρ', from which T' is extracted via the hidden-sector equation of state. The energy-transfer collision term, which receives contributions from inverse decays and 2→2 scatterings of SM particles into dark-sector states, dete

Load-bearing premise

The dark sector reaches and maintains internal thermal equilibrium at a single dark temperature T' whenever its self-interaction rate exceeds the Hubble rate, and it stays a single-temperature Maxwell–Boltzmann fluid through freeze-out.

What would settle it

Solve the full momentum-dependent Boltzmann equations at a benchmark point inside the allowed DFO region (for example, m_a=m_φ=3 GeV, m_χ=20 GeV on the relic-density contour) without imposing a common dark temperature; if the resulting relic density deviates from Ωh²=0.12 by more than the quoted uncertainty, the single-T' premise fails and the viable region is not as claimed.

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

If this is right

  • S-wave dark matter below about 10 GeV is not automatically excluded by CMB measurements, because the annihilation rate at recombination is suppressed relative to standard thermal freeze-out.
  • The DFO region yields indirect-detection signals—gamma rays from dwarf galaxies, synchrotron radio emission from galaxy clusters, and CMB energy injection—that are within reach of current and near-future instruments.
  • BBN imposes a lower bound on the mediator–SM coupling and, through the relic-density condition, an indirect lower bound on the DM–mediator coupling; for the benchmark masses this excludes part of the parameter space.
  • Direct detection is irrelevant for DFO because the mediator–quark couplings are feeble, in contrast to secluded freeze-out, which is ruled out by direct detection and CMB for light mediators.
  • A viable DFO region survives for each of the three mediator masses studied (250 MeV, 3 GeV, 30 GeV), so the mechanism is not limited to one mass scale.

Where Pith is reading between the lines

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

  • The paper fixes g_aχ = g_φχ throughout; it notes that the relic density and constraints depend on the product g_aχ g_φχ, so moderate asymmetries merely shift the allowed region, but large asymmetries switch the dominant annihilation to p-wave channels and weaken indirect-detection bounds—potentially opening additional viable regions.
  • The single-dark-temperature approximation could break down if kinetic decoupling inside the hidden sector occurs; a two-temperature treatment would test whether the shape of the relic-density contours is robust.
  • The same DFO machinery should apply to any model with an s-wave dark-sector annihilation channel and feeble portal couplings, so the qualitative conclusion—DFO evades CMB limits while remaining indirectly detectable—likely generalizes beyond this specific scalar/pseudoscalar construction.

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. This paper studies decoupled freeze-out (DFO) in a model with a Dirac fermion dark matter particle and a mass-degenerate scalar/pseudoscalar mediator pair. The dark sector is assumed to reach internal equilibrium at a temperature T' below the SM temperature T, and the observed relic density is set mainly by the s-wave process χχ→aφ. The authors derive four coupled Boltzmann equations for n_χ, n_a, n_φ, and the dark-sector energy density, solve them numerically, and map relic-density contours in the (m_χ, g_{aχ}=g_{φχ}) plane for mediator masses 250 MeV, 3 GeV, and 30 GeV. They then apply CMB, Fermi-LAT, MeerKAT radio, and BBN constraints, and compare the allowed DFO region with the secluded freeze-out scenario, concluding that DFO can remain viable where secluded freeze-out is excluded.

Significance. If the calculation is correct, the paper makes a useful contribution by demonstrating a concrete s-wave annihilation model in which DFO evades CMB bounds and remains accessible to indirect searches. The systematic treatment of constraints with micrOMEGAs, DarkMatters, and published BBN limits is valuable, as is the explicit comparison with secluded freeze-out. The main strengths are the detailed four-equation setup, the mass scan over three representative mediator masses, and the multimessenger constraint analysis. However, the central result depends critically on the hidden-sector single-temperature assumption and on the consistency of the two-temperature Boltzmann equations; these are not yet demonstrated to the standard required level.

major comments (3)
  1. [§3, Eq. (3.1), Fig. 2] The single-temperature hidden-sector assumption underpins the entire relic-density calculation, yet Eq. (3.1) is never evaluated along the relic-density contours of Fig. 2. For the smallest displayed couplings (g_{aχ}=g_{φχ} ~ 3×10^-3 GeV^-1, m_χ ~ 10 GeV), the s-wave χχ→aφ rate at T' ~ m_χ/20 is below H by orders of magnitude; the criterion in Eq. (3.1) then fails if T' falls that low before freeze-out. Since Eqs. (3.11)–(3.13) assume a common T' and Maxwell-Boltzmann equilibrium, the relic contours and the derived constraints are not controlled in the claimed viable region. Please show Γ_HS/H along the contours for the dominant hidden-sector processes, including elastic/kinetic processes, or redo the calculation allowing partial kinetic decoupling.
  2. [§3, Eq. (3.13)] The visible–hidden interaction terms in Eq. (3.13) do not consistently account for two temperatures. In the first term of dn_χ/dt, the loss process χχ→f\bar f is written with the same thermal average at T as the production term, although χ is at T' and f is at T; the correct Boltzmann collision integral requires <σv>(T') for the loss and <σv>(T) for production, with T-dependent n_f^eq. The same issue appears in the mediator equations for i a→jk and Γ_{a→f\bar f}. This is an internal inconsistency in the master equations. Even if the numerical impact is small because hidden-sector processes dominate, it needs to be quantified or the equations corrected.
  3. [§5, upper boundary of DFO region] The boundary separating DFO from the thermal/secluded regime is defined by a threshold in g_{aφ f} (e.g., g_{aφ f} ≳ 2.5×10^-10 GeV^-1 for m_a=250 MeV), but no quantitative criterion is given. The rate Γ_{HS↔SM}/H that defines this decoupling condition should be specified and evaluated, since the existence and location of the viable DFO window depend on it.
minor comments (4)
  1. [§5, p. 15] “For instance, for m_χ=250 MeV, once g... ” should read “for m_a=m_φ=250 MeV”; the dark matter mass scan starts at 5 GeV.
  2. [Tables 1–2] The third mass block (250 MeV) is not labelled; the column header “Scalar mass [GeV]” appears only for the first block. Please format the table so each mass block is clearly identified.
  3. [Notation] The paper switches between xσvy and ⟨σv⟩ in several places; please define the bracket notation once and use it consistently.
  4. [Fig. 2 caption] The caption describes the BBN exclusions as “contours” and “exclusion lines,” but they are shown as shaded regions; please clarify that each BBN exclusion is tied to a fixed value of g_{φ(a)f}.

Circularity Check

0 steps flagged

No significant circularity: the relic-density target is an external constraint, and the constraints come from independent data and codes.

full rationale

The paper's central claim is that for given masses a region of couplings exists where DFO produces the observed relic density while avoiding experimental bounds. This is obtained by solving the coupled system (3.2) and (3.13) and using bisection to adjust g_{aχ}=g_{ϕχ} to Ωh²=0.120; the target is external (Planck [33]), so this is constraint matching, not a fitted input renamed as a prediction. The CMB, Fermi-LAT, MeerKAT radio, and BBN exclusions are independent experimental/observational inputs applied after the relic-density calculation. The energy-transfer equations are taken from the literature ([19,21,22]) including the authors' earlier work, but they are technical derivations of collision integrals and do not assume the relic-density result; the code adaptation from [22] is a numerical implementation, not an argument that reduces the present conclusion to its input. The single-temperature hidden-sector assumption in Eqs. (3.1), (3.11)-(3.12) is a modeling premise whose quantitative validity is asserted rather than demonstrated, but an unquantified approximation is not circularity: it does not make the derived relic-density contours equal to an input by construction. No quotation in the paper exhibits the required reduction, such as Eq. X = Eq. Y by definition or a parameter fitted to a subset then used to 'predict' that same subset.

Axiom & Free-Parameter Ledger

6 free parameters · 8 axioms · 3 invented entities

The paper's central contribution is a parameter scan with standard Boltzmann and constraint machinery. The main model-building burden is the set of simplifying equalities (degenerate mediators, equal scalar/pseudoscalar couplings, zero Higgs portal and self-couplings) that define the scanned subspace. The new particles themselves have falsifiable handles through annihilation and decay signals, but are not independently evidenced.

free parameters (6)
  • Dark-sector coupling g_aχ = g_ϕχ = ~10^-3–10^-2 GeV^-1, set by bisection to Ωh²=0.120
    Determined by solving the Boltzmann equations until the relic density matches the Planck value. This is a fit to the observed relic abundance, not an independent measurement.
  • Mediator–SM coupling g_af = g_ϕf = 10^-13–10^-10 GeV^-1 along the shown contours
    Chosen by hand to define relic-density contours; it controls energy transfer into the hidden sector and the mediator decay lifetimes.
  • Mediator masses m_a = m_ϕ = 250 MeV, 3 GeV, 30 GeV
    Benchmark choices, not fitted to data, chosen to represent muonic, hadronic, and weak-scale decay regimes.
  • DM mass m_χ = 5 GeV to M_W, scanned
    Scanned range with the condition m_χ > m_a,m_ϕ so that χχ→aϕ is kinematically open.
  • Reheating temperature T_RH = 10^4 GeV
    Chosen by hand. The paper argues higher-dimensional operator contributions are mild for DFO, but freeze-in-like contributions can depend on T_RH.
  • Coupling and mass degeneracy ansatz = r = g_aχ/g_ϕχ = 1, m_a = m_ϕ, g_af = g_ϕf
    This defines the scanned subspace. Deviations are discussed only qualitatively in Sec. 7.
axioms (8)
  • domain assumption The dark sector starts with negligible particle abundances after reheating.
    Sec. 3; the DFO scenario is defined by this initial condition. If dark-sector particles were initially abundant, the energy-transfer and T' evolution would be different.
  • domain assumption The hidden sector reaches and maintains internal thermal equilibrium at a single dark temperature T' when Γ_HS > H.
    Sec. 3, Eq. (3.1); load-bearing because a common T' is used in the equilibrium equation of state and in all hidden-sector thermally averaged cross sections.
  • domain assumption Backreaction from dark-sector to SM scattering is negligible because T' << T.
    Sec. 3; used to justify the one-way energy-transfer Boltzmann equation.
  • domain assumption All species are described by Maxwell-Boltzmann statistics.
    Sec. 3; affects thermally averaged cross sections, decay rates, and the hidden-sector energy density.
  • ad hoc to paper The scalar-Higgs portal couplings and mediator self-couplings are set to zero.
    Sec. 2; chosen to isolate the Yukawa interactions. Nonzero self-couplings could change dark-sector thermalization and open new processes.
  • ad hoc to paper Equal mediator masses and equal scalar/pseudoscalar couplings: m_a=m_ϕ, g_aχ=g_ϕχ, g_af=g_ϕf.
    Secs. 3 and 5; defines the subspace scanned. The ratio r is only discussed qualitatively in Sec. 7.
  • domain assumption The EFT cutoff lies above all relevant scales; higher-dimensional operators and finite-temperature effects are neglected.
    Sec. 3; the paper argues the relic density is IR-dominated for DFO, but the freeze-in component can depend on the cutoff and T_RH.
  • standard math The SM bath remains in thermal equilibrium at temperature T with g* taken from Ref. [42].
    Sec. 3; standard cosmological input for the SM energy density and Hubble rate.
invented entities (3)
  • Dirac fermion dark matter χ independent evidence
    purpose: Dark matter candidate, odd under Z2, annihilating s-wave into aφ in the DFO scenario.
    The model predicts χχ→aφ→4 SM particles, giving gamma-ray, radio, and CMB signatures constrained by Fermi-LAT, MeerKAT, and Planck. No positive detection exists, but the annihilation cross-section is a falsifiable handle.
  • Scalar mediator φ independent evidence
    purpose: Mediates DM-SM interactions; feebly coupled to SM fermions, long-lived, and can affect BBN and indirect signals.
    Its decay width and lifetime set BBN constraints and its couplings set predicted gamma/radio fluxes; these are handles from outside the model assumptions.
  • Pseudoscalar mediator a (ALP-like) independent evidence
    purpose: Together with φ allows the dominant s-wave annihilation χχ→aφ; feebly coupled to SM and long-lived.
    BBN lifetime limits and indirect-detection constraints provide falsifiable signals; no direct evidence of existence is claimed.

pith-pipeline@v1.3.0-alltime-deepseek · 22418 in / 16075 out tokens · 164656 ms · 2026-08-03T21:33:33.264928+00:00 · methodology

0 comments
read the original abstract

We consider a model of dark matter where the mediator corresponds to a superposition of a scalar and pseudoscalar, and the scenario where, after reheating, the number densities of the dark sector particles, i.e. the dark matter and the mediators, are negligible. If the coupling of the mediators to the Standard Model is feeble, but the coupling to the dark matter is large enough, the dark sector may reach equilibrium at a temperature distinct from that of the thermal bath. The relic density is then said to be obtained via decoupled freeze out (DFO). We focus on the $s$-wave annihilation scenario, which particularly benefits from the DFO mechanism by evading standard CMB limits while still yielding indirect detection signals. We calculate the relic density by solving a set of four coupled Boltzmann equations for the number densities of the dark sector particles and the energy transfer from the light to dark sector. We finally perform a thorough analysis of experimental bounds on this scenario, namely from indirect detection and the CMB, as well as from BBN, and find that, while there are considerable constraints on the parameter space where the correct relic density is obtained, a viable region remains to be explored.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

67 extracted references · 61 linked inside Pith

  1. [1]

    Cirelli, A

    M. Cirelli, A. Strumia and J. Zupan,Dark Matter,2406.01705. – 23 – Channel Pseudoscalar mass [GeV] Mass of decaying particles [GeV] Decay width [GeV] Branching Fraction [%] µ¯µ 30 105.7ˆ10 ´3 1.334ˆ10 ´2 0.02 τ¯τ 1.777 3.743 5.33 c¯c 1.270 5.755 8.20 b¯b 4.180 60.09 85.65 gg 0 0.555 0.79 µ¯µ 3 105.7ˆ10 ´3 1.330ˆ10 ´3 3.65 s¯s 93.4ˆ10 ´3 3.118ˆ10 ´3 8.56 g...

  2. [2]

    McDonald,Thermally generated gauge singlet scalars as selfinteracting dark matter,Phys

    J. McDonald,Thermally generated gauge singlet scalars as selfinteracting dark matter,Phys. Rev. Lett.88(2002) 091304 [hep-ph/0106249]

  3. [3]

    L.J. Hall, K. Jedamzik, J. March-Russell and S.M. West,Freeze-In Production of FIMP Dark Matter,JHEP03(2010) 080 [0911.1120]

  4. [4]

    Bernal, M

    N. Bernal, M. Heikinheimo, T. Tenkanen, K. Tuominen and V. Vaskonen,The Dawn of FIMP Dark Matter: A Review of Models and Constraints,Int. J. Mod. Phys. A32(2017) 1730023 [1706.07442]

  5. [5]

    Pospelov, A

    M. Pospelov, A. Ritz and M.B. Voloshin,Secluded WIMP Dark Matter,Phys. Lett. B662 (2008) 53 [0711.4866]

  6. [6]

    D’Agnolo and J.T

    R.T. D’Agnolo and J.T. Ruderman,Light Dark Matter from Forbidden Channels,Phys. Rev. Lett.115(2015) 061301 [1505.07107]

  7. [7]

    D’Agnolo, D

    R.T. D’Agnolo, D. Liu, J.T. Ruderman and P.-J. Wang,Forbidden dark matter annihilations into Standard Model particles,JHEP06(2021) 103 [2012.11766]

  8. [8]

    Belanger and J.-C

    G. Belanger and J.-C. Park,Assisted freeze-out,JCAP03(2012) 038 [1112.4491]

  9. [9]

    Zurek,Multi-Component Dark Matter,Phys

    K.M. Zurek,Multi-Component Dark Matter,Phys. Rev. D79(2009) 115002 [0811.4429]

  10. [10]

    Liu, Y.-L

    Z.-P. Liu, Y.-L. Wu and Y.-F. Zhou,Enhancement of dark matter relic density from the late time dark matter conversions,Eur. Phys. J. C71(2011) 1749 [1101.4148]

  11. [11]

    Belanger, K

    G. Belanger, K. Kannike, A. Pukhov and M. Raidal,Impact of semi-annihilations on dark matter phenomenology - an example ofZN symmetric scalar dark matter,JCAP04(2012) 010 [1202.2962]

  12. [12]

    S. Esch, M. Klasen and C.E. Yaguna,A minimal model for two-component dark matter, JHEP09(2014) 108 [1406.0617]

  13. [13]

    Arcadi, C

    G. Arcadi, C. Gross, O. Lebedev, Y. Mambrini, S. Pokorski and T. Toma,Multicomponent Dark Matter from Gauge Symmetry,JHEP12(2016) 081 [1611.00365]

  14. [14]

    Chakraborti and P

    S. Chakraborti and P. Poulose,Interplay of Scalar and Fermionic Components in a Multi-component Dark Matter Scenario,Eur. Phys. J. C79(2019) 420 [1808.01979]. – 24 –

  15. [15]

    Chakraborti, A

    S. Chakraborti, A. Dutta Banik and R. Islam,Probing Multicomponent Extension of Inert Doublet Model with a Vector Dark Matter,Eur. Phys. J. C79(2019) 662 [1810.05595]

  16. [16]

    Belanger, A

    G. Belanger, A. Mjallal and A. Pukhov,Two dark matter candidates: The case of inert doublet and singlet scalars,Phys. Rev. D105(2022) 035018 [2108.08061]

  17. [17]

    Bélanger, A

    G. Bélanger, A. Pukhov, C.E. Yaguna and Ó. Zapata,The Z7 model of three-component scalar dark matter,JHEP03(2023) 100 [2212.07488]

  18. [18]

    J.L. Feng, A. Rajaraman and F. Takayama,SuperWIMP dark matter signals from the early universe,Phys. Rev. D68(2003) 063504 [hep-ph/0306024]

  19. [19]

    Hambye, M.H.G

    T. Hambye, M.H.G. Tytgat, J. Vandecasteele and L. Vanderheyden,Dark matter from dark photons: a taxonomy of dark matter production,Phys. Rev. D100(2019) 095018 [1908.09864]

  20. [20]

    Bélanger, C

    G. Bélanger, C. Delaunay, A. Pukhov and B. Zaldivar,Dark matter abundance from the sequential freeze-in mechanism,Phys. Rev. D102(2020) 035017 [2005.06294]

  21. [21]

    X. Chu, T. Hambye and M.H.G. Tytgat,The Four Basic Ways of Creating Dark Matter Through a Portal,JCAP05(2012) 034 [1112.0493]

  22. [22]

    Bharucha, F

    A. Bharucha, F. Brümmer, N. Desai and S. Mutzel,Axion-like particles as mediators for dark matter: beyond freeze-out,JHEP02(2023) 141 [2209.03932]

  23. [23]

    Binder, T

    T. Binder, T. Bringmann, M. Gustafsson and A. Hryczuk,Early kinetic decoupling of dark matter: when the standard way of calculating the thermal relic density fails,Phys. Rev. D96 (2017) 115010 [1706.07433]

  24. [24]

    Binder, T

    T. Binder, T. Bringmann, M. Gustafsson and A. Hryczuk,Dark matter relic abundance beyond kinetic equilibrium,Eur. Phys. J. C81(2021) 577 [2103.01944]

  25. [25]

    Binder, S

    T. Binder, S. Chakraborti, S. Matsumoto and Y. Watanabe,A global analysis of resonance-enhanced light scalar dark matter,JHEP01(2023) 106 [2205.10149]

  26. [26]

    Bélanger, S

    G. Bélanger, S. Chakraborti, Y. Génolini and P. Salati,GeV-scale dark matter with p-wave Breit-Wigner enhanced annihilation,Phys. Rev. D110(2024) 023039 [2401.02513]

  27. [27]

    Bélanger, S

    G. Bélanger, S. Chakraborti, C. Delaunay and M. Jomain,Rekindling s-Wave Dark Matter Annihilation Below 10GeV with Breit-Wigner Effects,2503.08897

  28. [28]

    Garny, J

    M. Garny, J. Heisig, B. Lülf and S. Vogl,Coannihilation without chemical equilibrium,Phys. Rev. D96(2017) 103521 [1705.09292]

  29. [29]

    D’Agnolo, D

    R.T. D’Agnolo, D. Pappadopulo and J.T. Ruderman,Fourth Exception in the Calculation of Relic Abundances,Phys. Rev. Lett.119(2017) 061102 [1705.08450]

  30. [30]

    Brümmer,Coscattering in next-to-minimal dark matter and split supersymmetry,JHEP 01(2020) 113 [1910.01549]

    F. Brümmer,Coscattering in next-to-minimal dark matter and split supersymmetry,JHEP 01(2020) 113 [1910.01549]

  31. [31]

    Alguero, G

    G. Alguero, G. Belanger, S. Kraml and A. Pukhov,Co-scattering in micrOMEGAs: A case study for the singlet-triplet dark matter model,SciPost Phys.13(2022) 124 [2207.10536]

  32. [32]

    Slatyer,Indirect dark matter signatures in the cosmic dark ages

    T.R. Slatyer,Indirect dark matter signatures in the cosmic dark ages. I. Generalizing the bound on s-wave dark matter annihilation from Planck results,Phys. Rev. D93(2016) 023527 [1506.03811]. [33]Planckcollaboration,Planck 2018 results. VI. Cosmological parameters,Astron. Astrophys. 641(2020) A6 [1807.06209]. – 25 – [34]Fermi-LATcollaboration,Searching f...

  33. [35]

    Knowles et al.,The MeerKAT Galaxy Cluster Legacy Survey - I

    K. Knowles et al.,The MeerKAT Galaxy Cluster Legacy Survey - I. Survey Overview and Highlights,Astron. Astrophys.657(2022) A56 [2111.05673]

  34. [36]

    Jonas,The MeerKAT Radio Telescope, inProceedings of MeerKAT Science: On the Pathway to the SKA — PoS(MeerKAT2016), vol

    J. Jonas,The MeerKAT Radio Telescope, inProceedings of MeerKAT Science: On the Pathway to the SKA — PoS(MeerKAT2016), vol. 277, p. 001, 2018, DOI

  35. [37]

    Beck and S

    G. Beck and S. Makhathini,Just a MeerKAT, or a dark matter machine?, 1, 2023 [2301.07910]

  36. [38]

    Nomura and J

    Y. Nomura and J. Thaler,Dark Matter through the Axion Portal,Phys. Rev. D79(2009) 075008 [0810.5397]

  37. [39]

    Djouadi,The Anatomy of electro-weak symmetry breaking

    A. Djouadi,The Anatomy of electro-weak symmetry breaking. I: The Higgs boson in the standard model,Phys. Rept.457(2008) 1 [hep-ph/0503172]

  38. [40]

    Djouadi,The Anatomy of electro-weak symmetry breaking

    A. Djouadi,The Anatomy of electro-weak symmetry breaking. II. The Higgs bosons in the minimal supersymmetric model,Phys. Rept.459(2008) 1 [hep-ph/0503173]

  39. [41]

    Gondolo and G

    P. Gondolo and G. Gelmini,Cosmic abundances of stable particles: Improved analysis,Nucl. Phys. B360(1991) 145

  40. [42]

    Saikawa and S

    K. Saikawa and S. Shirai,Primordial gravitational waves, precisely: The role of thermodynamics in the Standard Model,JCAP05(2018) 035 [1803.01038]

  41. [43]

    Alguero, G

    G. Alguero, G. Belanger, F. Boudjema, S. Chakraborti, A. Goudelis, S. Kraml et al., micrOMEGAs 6.0: N-component dark matter,Comput. Phys. Commun.299(2024) 109133 [2312.14894]

  42. [44]

    Profumo, F.S

    S. Profumo, F.S. Queiroz, J. Silk and C. Siqueira,Searching for Secluded Dark Matter with H.E.S.S., Fermi-LAT, and Planck,JCAP03(2018) 010 [1711.03133]

  43. [45]

    Y.-H. Su, C. Cai and H.-H. Zhang,Constraining secluded and catalyzed-annihilation dark matter models with Fermi-LAT and Planck data,Phys. Rev. D111(2025) 075013 [2501.09647]

  44. [46]

    Datta, S

    A. Datta, S. Roy, A.K. Saha and A. Tapadar,An EFT origin of Secluded Dark Matter, 2312.17171

  45. [47]

    Y. Du, F. Huang, H.-L. Li and J.-H. Yu,Freeze-in Dark Matter from Secret Neutrino Interactions,JHEP12(2020) 207 [2005.01717]. [48]ANTAREScollaboration,Search for secluded dark matter towards the Galactic Centre with the ANTARES neutrino telescope,JCAP06(2022) 028 [2203.06029]

  46. [49]

    Natarajan, J.E

    A. Natarajan, J.E. Aguirre, K. Spekkens and B.S. Mason,Green Bank Telescope Constraints on Dark Matter Annihilation in Segue I,1507.03589

  47. [50]

    Booth, W.J.G

    R.S. Booth, W.J.G. de Blok, J.L. Jonas and B. Fanaroff,MeerKAT Key Project Science, Specifications, and Proposals,0910.2935

  48. [51]

    Cembranos, Á

    J.A.R. Cembranos, Á. De La Cruz-Dombriz, V. Gammaldi and M. Méndez-Isla,SKA-Phase 1 sensitivity to synchrotron radio emission from multi-TeV Dark Matter candidates,Phys. Dark Univ.27(2020) 100448 [1905.11154]

  49. [52]

    Lavis, M

    N. Lavis, M. Sarkis, G. Beck and K. Knowles,Radio-frequency WIMP search with the MeerKAT galaxy cluster legacy survey,Phys. Rev. D108(2023) 123536 [2308.08351]. – 26 –

  50. [53]

    Sarkis and G

    M. Sarkis and G. Beck,DarkMatters: A powerful tool for WIMPy analysis,Phys. Dark Univ. 47(2025) 101745 [2408.07053]

  51. [54]

    Bergstrom, P

    L. Bergstrom, P. Ullio and J.H. Buckley,Observability of gamma-rays from dark matter neutralino annihilations in the Milky Way halo,Astropart. Phys.9(1998) 137 [astro-ph/9712318]

  52. [55]

    Navarro, C.S

    J.F. Navarro, C.S. Frenk and S.D.M. White,A Universal density profile from hierarchical clustering,Astrophys. J.490(1997) 493 [astro-ph/9611107]

  53. [56]

    Calore, B

    F. Calore, B. Zaldívar, P. Serpico and C. Eckner,Dark matter constraints from dwarf galaxies: a data-driven lat analysis, Oct., 2021. 10.5281/zenodo.5592836

  54. [57]

    Alvarez, F

    A. Alvarez, F. Calore, A. Genina, J. Read, P.D. Serpico and B. Zaldivar,Dark matter constraints from dwarf galaxies with data-driven J-factors,JCAP09(2020) 004 [2002.01229]

  55. [58]

    Calore, P.D

    F. Calore, P.D. Serpico and B. Zaldivar,Dark matter constraints from dwarf galaxies: a data-driven analysis,JCAP10(2018) 029 [1803.05508]

  56. [59]

    Kawasaki, K

    M. Kawasaki, K. Kohri, T. Moroi and Y. Takaesu,Revisiting Big-Bang Nucleosynthesis Constraints on Long-Lived Decaying Particles,Phys. Rev. D97(2018) 023502 [1709.01211]

  57. [60]

    Kawasaki, K

    M. Kawasaki, K. Kohri, T. Moroi, K. Murai and H. Murayama,Big-bang nucleosynthesis with sub-GeV massive decaying particles,JCAP12(2020) 048 [2006.14803]

  58. [61]

    Protheroe, T

    R.J. Protheroe, T. Stanev and V.S. Berezinsky,Electromagnetic cascades and cascade nucleosynthesis in the early universe,Phys. Rev. D51(1995) 4134 [astro-ph/9409004]

  59. [62]

    Kawasaki and T

    M. Kawasaki and T. Moroi,Electromagnetic cascade in the early universe and its application to the big bang nucleosynthesis,Astrophys. J.452(1995) 506 [astro-ph/9412055]

  60. [63]

    Coffey, L

    J. Coffey, L. Forestell, D.E. Morrissey and G. White,Cosmological Bounds on sub-GeV Dark Vector Bosons from Electromagnetic Energy Injection,JHEP07(2020) 179 [2003.02273]

  61. [64]

    Cadamuro and J

    D. Cadamuro and J. Redondo,Cosmological bounds on pseudo Nambu-Goldstone bosons, JCAP02(2012) 032 [1110.2895]

  62. [65]

    G. N. Fortes, F. S. Queiroz, C. Siqueira and A. Viana,Present and future constraints on secluded dark matter in the Galactic Halo with TeV Gamma-ray observatories,JCAP07 (2023) 043 [2212.05075]. [66]PandaX-4Tcollaboration,Dark Matter Search Results from the PandaX-4T Commissioning Run,Phys. Rev. Lett.127(2021) 261802 [2107.13438]. [67]LZcollaboration,Dark...

  63. [68]

    Aalbers et al.,A next-generation liquid xenon observatory for dark matter and neutrino physics,J

    J. Aalbers et al.,A next-generation liquid xenon observatory for dark matter and neutrino physics,J. Phys. G50(2023) 013001 [2203.02309]

  64. [69]

    Dvorkin et al.,Dark Matter Physics from the CMB-S4 Experiment, inSnowmass 2021, 3, 2022 [2203.07064]

    C. Dvorkin et al.,Dark Matter Physics from the CMB-S4 Experiment, inSnowmass 2021, 3, 2022 [2203.07064]. [70]e-ASTROGAMcollaboration,Science with e-ASTROGAM: A space mission for MeV–GeV gamma-ray astrophysics,JHEAp19(2018) 1 [1711.01265]

  65. [71]

    Dzhatdoev and E

    T. Dzhatdoev and E. Podlesnyi,Massive Argon Space Telescope (MAST): A concept of heavy time projection chamber forγ-ray astronomy in the 100 MeV–1 TeV energy range,Astropart. Phys.112(2019) 1 [1902.01491]. – 27 –

  66. [72]

    O’Donnell and T.R

    K.E. O’Donnell and T.R. Slatyer,Constraints on dark matter with future MeV gamma-ray telescopes,Phys. Rev. D111(2025) 083037 [2411.00087]

  67. [73]

    Wang, Z.-F

    G.-S. Wang, Z.-F. Chen, L. Zu, H. Gong, L. Feng and Y.-Z. Fan,SKA sensitivity for possible radio emission from dark matter in Omega Centauri,JCAP05(2024) 129 [2303.14117]. – 28 –