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Decaying dark matter via neutrinophilic channel suppresses late-time clustering enough to ease the S8 tension while fitting DES data.

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-4.3

2026-06-28 18:27 UTC pith:NHRCMTCT

load-bearing objection This applies an existing decaying dark matter idea to the S8 tension with DES Y1 but stays at the level of an exploration without enough technical detail to check the fits. the 2 major comments →

arxiv 2606.00529 v1 pith:NHRCMTCT submitted 2026-05-30 astro-ph.CO hep-ph

Decaying Dark Matter as a Possible Solution for Cosmological Tensions

Yaman Acharya , Ryan E. Johnson This is my paper
classification astro-ph.CO hep-ph
keywords decaying dark matterS8 tensioncosmological tensionsneutrinophilic decaylarge-scale structureDES surveyweak lensingmatter power spectrum
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 paper tests whether a decaying dark matter model can resolve the mismatch in the structure growth parameter S8 between early-universe and late-universe observations. It focuses on a heavy dark matter particle that decays slowly into a Standard Model neutrino and a light invisible fermion. This process changes the expansion history and damps the growth of density fluctuations at late times in a scale-dependent way. When the resulting angular power spectra are compared to DES Year 1 measurements, the model remains consistent with the data yet produces a lower S8 value that better matches weak-lensing surveys.

Core claim

Slow decay through the channel χ → ν + φ generates a scale-dependent suppression of matter clustering that stays compatible with DES galaxy-galaxy, shear-shear, and galaxy-shear spectra while shifting the predicted structure amplitude downward toward the range preferred by weak-lensing data.

What carries the argument

The neutrinophilic decay channel χ → ν + φ, which simultaneously alters background evolution and the growth of perturbations at late times.

Load-bearing premise

A decay lifetime and branching ratio exist that produce the needed late-time suppression without violating other cosmological or particle-physics limits.

What would settle it

A measurement of the small-scale matter power spectrum or a direct search for the decay products that fails to show the predicted suppression would rule out the model.

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

If this is right

  • The suppression remains consistent with all three DES angular power spectra.
  • The predicted S8 moves closer to the lower values reported by weak-lensing analyses.
  • Both background expansion and perturbation growth are modified together by the same decay process.
  • The effect is scale-dependent rather than uniform across all wavenumbers.

Where Pith is reading between the lines

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

  • Future surveys with finer redshift bins could isolate the scale dependence as a distinctive signature.
  • The same decay parameters might be checked against CMB lensing or cluster abundance data for consistency.
  • If the channel is realized in a particle model, laboratory bounds on neutrino-DM interactions would become relevant.
  • Alternative decay channels could be compared to see whether the neutrinophilic route is uniquely favored by the S8 shift.

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

2 major / 0 minor

Summary. The manuscript proposes decaying dark matter (DDM) with a neutrinophilic decay channel χ → ν + φ as a solution to the S8 tension. It modifies background evolution and perturbations to produce late-time, scale-dependent suppression of clustering. Using DES Year 1 redshift distributions, the authors compute galaxy-galaxy, shear-shear, and galaxy-shear angular power spectra in both ΛCDM and DDM scenarios, claiming consistency with DES data while shifting the predicted structure amplitude to lower values favored by weak-lensing surveys.

Significance. If the quantitative results hold after full derivation and validation, the work would supply a physically motivated, late-time mechanism that simultaneously preserves consistency with DES angular spectra and lowers inferred S8, offering a concrete alternative to extensions of ΛCDM for resolving the structure-growth tension.

major comments (2)
  1. Abstract: the central claim that slow decay produces a scale-dependent suppression 'consistent with DES measurements' while lowering S8 cannot be evaluated because no decay lifetime, mass ratio, or perturbation equations are supplied; without these the asserted effect remains unverified against the paper's own formalism.
  2. Abstract: the statement that the model 'naturally shifts the predicted structure amplitude' lacks any reported parameter values, fit statistics, or comparison of S8 posteriors between ΛCDM and DDM, so the quantitative relief of the tension cannot be assessed.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their comments. We respond point-by-point to the major comments on the abstract below and indicate where revisions will be made.

read point-by-point responses

  1. Referee: Abstract: the central claim that slow decay produces a scale-dependent suppression 'consistent with DES measurements' while lowering S8 cannot be evaluated because no decay lifetime, mass ratio, or perturbation equations are supplied; without these the asserted effect remains unverified against the paper's own formalism.

    Authors: We agree that the abstract does not contain the explicit decay lifetime, mass ratio, or perturbation equations, as these details are reserved for the main text. The manuscript derives the modified background and perturbation equations for the neutrinophilic decay channel in Section 2, specifies the explored parameter ranges (decay rate and mass splitting) in Section 3, and verifies the scale-dependent suppression via the angular power spectra computed with DES Year 1 redshift distributions. To address the concern, we will revise the abstract to include a brief reference to the key parameters and the location of the formalism. revision: yes

  2. Referee: Abstract: the statement that the model 'naturally shifts the predicted structure amplitude' lacks any reported parameter values, fit statistics, or comparison of S8 posteriors between ΛCDM and DDM, so the quantitative relief of the tension cannot be assessed.

    Authors: The abstract summarizes the qualitative outcome. The full manuscript reports the specific parameter values, the S8 posterior shifts between the two models, and the associated fit statistics (including chi-squared comparisons) in the results section. We will revise the abstract to note the quantitative S8 shift and consistency with DES data as quantified in the main text. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The provided abstract and description outline a standard model extension where DDM parameters alter background evolution and perturbation growth, followed by computation of angular power spectra using DES Y1 redshift distributions as input. No equations, fitting procedures, or self-citations are shown that reduce the claimed scale-dependent suppression or S8 shift to a tautology or to the same data used for validation. The central claim remains a forward computation of modified spectra compared against external measurements, with no load-bearing step that collapses by construction to its inputs.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review prevents enumeration of free parameters, axioms, or invented entities; no equations or model details supplied.

pith-pipeline@v0.9.1-grok · 5729 in / 1008 out tokens · 14879 ms · 2026-06-28T18:27:00.887515+00:00 · methodology

0 comments
read the original abstract

Large-scale structure measurements have revealed persistent tensions between early- and late-time cosmological probes, most notably the long-standing discrepancy in the structure-growth parameter $S_8$. In this work, we explore how a model including decaying dark matter (DDM) can alleviate this tension by suppressing the growth of matter fluctuations at late times. Specifically, we consider a neutrinophilic decay channel in which a heavy dark matter particle $\chi$ slowly decays into a Standard Model neutrino and a light invisible fermion, $\chi \rightarrow \nu + \phi$, modifying both the background evolution and the clustering of structure. Using the DES Year~1 redshift distributions, we construct a baseline matter power spectrum and compute the galaxy-galaxy, shear-shear, and galaxy-shear angular power spectra under both $\Lambda$CDM and DDM-inspired scenarios. We find that slow dark matter decay produces a scale-dependent suppression of clustering that remains consistent with DES measurements while naturally shifting the predicted structure amplitude toward the lower values favored by weak lensing surveys. Our results suggest that decaying dark matter is a compelling and physically motivated framework for addressing the $S_8$ tension.

discussion (0)

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Is dark matter decaying ?

    astro-ph.CO 2026-06 unverdicted novelty 2.0

    Uncertainties in measuring today's matter content prevent confirming or ruling out dark matter decay, but upcoming surveys could change that.

Reference graph

Works this paper leans on

32 extracted references · 6 canonical work pages · cited by 1 Pith paper · 4 internal anchors

  1. [1]

    Physical Review D

    DES Collaboration, Dark Energy Survey year 1 results: Cosmological constraints from galaxy clustering and weak lensing. Physical Review D . 98 043526 (2018)

    2018

  2. [2]

    112 083515 (2025)

    DESI Collaboration, DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints, Physical Review D . 112 083515 (2025)

    2025

  3. [3]

    98 042005 (2018)

    DES Collaboration, Dark Energy Survey year 1 results: Galaxy-galaxy lensing , Physical Review D. 98 042005 (2018)

    2018

  4. [4]

    DES Collaboration ( T. M. C. Abbott et al) First Cosmology Results Using Type Ia Supernovae from the Dark Energy Survey: Constraints on Cosmological Parameters. The Astrophysical Journal Letters . 872 pp. L30 (2018)

    2018

  5. [5]

    & Winkler, M

    Freese, K. & Winkler, M. Dark Matter and Gravity Waves from a Dark Big Bang. Physical Review D . volume 107, issue 8, 083522, (2023)

    2023

  6. [6]

    & Das, S

    Pandey, K., Karwal, T. & Das, S. Alleviating the H0 and σ8 anomalies with a decaying dark matter model. Journal of Cosmology and Astroparticle Physics . JCAP07, 026, (2020)

    2020

  7. [7]

    & Winkler, M

    Freese, K. & Winkler, M. Chain Early Dark Energy: A Proposal for solving the Hubble tension and explaining todays dark energy. Physical Review D . 104, 083533 (2021)

    2021

  8. [8]

    Dark matterneutrino interactions through the lens of their cosmological implications

    Olivares-Del Campo, A., Boehm, C., Palomares-Ruiz, S., Pascoli, S. Dark matterneutrino interactions through the lens of their cosmological implications. Physical Review D . 97 pp. 075039 (2018)

    2018

  9. [9]

    & Others Dark Energy Survey Year 3 Results: Cosmological constraints from second and third-order shear statistics

    DES Collaboration, Gomes, R., Sugiyama, S., Jain, B., Jarvis, M., Anbajagane, D., Halder, A. & Others Dark Energy Survey Year 3 Results: Cosmological constraints from second and third-order shear statistics. Physical Review D . 112, 12, 123515 (2025) – 14 –

    2025

  10. [10]

    & Others Interacting Dark Sector (ETHOS n=0): Cosmological Constraints from SPT Cluster Abundance with DES and HST Weak Lensing Data

    Mazoun, A., Bocquet, S., Mohr, J., Garny, M., Rubira, H. & Others Interacting Dark Sector (ETHOS n=0): Cosmological Constraints from SPT Cluster Abundance with DES and HST Weak Lensing Data. Physical Review D , Volume 111, i, 083543, 19, (2025)

    2025

  11. [11]

    & Maartens, R

    Böhmer, C., Caldera-Cabral, G., Lazkoz, R. & Maartens, R. Dynamics of dark energy with a coupling to dark matter. Physical Review D . 78, 023505 (2008)

    2008

  12. [12]

    The Analysis of Counts of the Extragalactic Nebulae in Terms of a Fluctuating Density Field

    Limber, D. The Analysis of Counts of the Extragalactic Nebulae in Terms of a Fluctuating Density Field. The Astrophysical Journal . 117 pp. 134 (1953)

    1953

  13. [13]

    & Others Cosmological constraints from the tomography of DES-Y3 galaxies with CMB lensing from ACT DR4

    Marques, G., Madhavacheril, M., Darwish, O., Shaikh, S., Aguena, M., Alves, O., A vila, S., Bacon, D., Baxter, E., Bechtol, K. & Others Cosmological constraints from the tomography of DES-Y3 galaxies with CMB lensing from ACT DR4. Journal Of Cosmology And Astroparticle Physics. 2024, 033 (2024)

    2024

  14. [14]

    Tsallis-Cirto Hubble parameter: Explaining DESI data and High redshift Supermassive Black Hole

    Wong, J. Variable Modified Newtonian Mechanics VII: High redshift Supermassive Black Hole growth under an alternative Hubble Parameter. ArXiv Preprint ArXiv:2506.05423 . (2025), https://arxiv.org/abs/2506.05423

    work page internal anchor Pith review Pith/arXiv arXiv 2025

  15. [15]

    & Orito, S

    Hiroshima, N., Ishida, H., Murase, K. & Orito, S. High-energy neutrinos from multibody decaying dark matter. Physical Review D . 97, 023006 (2018)

    2018

  16. [16]

    & Ibarra, A

    FuSS, L., Garny, M. & Ibarra, A. Connecting cosmologically decaying dark matter to neutrino physics. (2025,9,23), https://arxiv.org/abs/2509.19596

    work page arXiv 2025

  17. [17]

    & White, S

    Davis, M., Efstathiou, G., Frenk, C. & White, S. The evolution of large-scale structure in a universe dominated by cold dark matter. The Astrophysical Journal . 292, 371-394 (1985), https://ui.adsabs.harvard.edu/abs/1985ApJ...292..371D

    1985

  18. [18]

    & Wagoner, E

    Chisari, N., Alonso, D., Krause, E., Leonard, C., Bull, P., Neveu, J., Villarreal, A., Singh, S., McClintock, T., Ellison, J., Du, Z., Zuntz, J., Mead, A., Joudaki, S., Lorenz, C., Tröster, T., Sanchez, J., Lanusse, F., Ishak, M., Hlozek, R., Blazek, J., Campagne, J., Almoubayyed, H., Eifler, T., Kirby, M., Kirkby, D., Plaszczynski, S., Slosar, A., Vrastil...

    2019

  19. [19]

    CosmoHammer: Cosmological parameter estimation with the MCMC Hammer

    Akeret, J., Seehars, S., Amara, A., Refregier, A. & Csillaghy, A. CosmoHammer: Cosmological parameter estimation with the MCMC Hammer. Astronomy And Computing . 2 pp. 27-39 (2013), https://arxiv.org/abs/1212.1721

    work page internal anchor Pith review Pith/arXiv arXiv 2013

  20. [20]

    Plank Collaboration, Planck 2018 results. VI. Cosmological parameters. Astronomy & Astrophysics. 641 pp. A6 (2020), https://arxiv.org/abs/1807.06209

    work page internal anchor Pith review Pith/arXiv arXiv 2018

  21. [21]

    & Tsujikawa, S

    Copeland, E., Sami, M. & Tsujikawa, S. Dynamics of dark energy. International Journal Of Modern Physics D . 15, 1753-1936 (2006)

    1936

  22. [22]

    & Others A Step in Understanding the S 8 Tension

    Joseph, M. & Others A Step in Understanding the S 8 Tension. (2022)

    2022

  23. [23]

    & Others KiDS-450: Cosmological parameter constraints from tomographic weak gravitational lensing

    Hildebrandt, H., Viola, M., Heymans, C., Joudaki, S., Kuijken, K. & Others KiDS-450: Cosmological parameter constraints from tomographic weak gravitational lensing. Monthly Notices Of The Royal Astronomical Society . 465, 1454-1498 (2017)

    2017

  24. [24]

    (2018), https://github.com/LSSTDESC/CCL

    LSST Dark Energy Science Collaboration Core Cosmology Library (CCL). (2018), https://github.com/LSSTDESC/CCL

    2018

  25. [25]

    Blumenthal, G., Faber, S., Primack, J. et al. Formation of galaxies and large-scale structure with cold dark matter.Nature 311, 517525 (1984). https://doi.org/10.1038/311517a0

    work page doi:10.1038/311517a0 1984

  26. [26]

    H., Markevitch, M., Randall, S

    Clowe, D., Brada, M., Gonzalez, A. H., Markevitch, M., Randall, S. W., Jones, C., & Zaritsky, D. (2006). A direct empirical proof of the existence of dark matter. The Astrophysical Journal , 648(2), L109-L113. – 15 –

    2006

  27. [27]

    Probing the Outskirts of the Early-Stage Galaxy Cluster Merger A1750 The Astrophysical Journal 2016, 818, 131

    Esra Bulbul et al. Probing the Outskirts of the Early-Stage Galaxy Cluster Merger A1750 The Astrophysical Journal 2016, 818, 131

    2016

  28. [28]

    Riess, Adam G. et al. Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant. The Astronomical Journal , 116, 1009 (1998)

    1998

  29. [29]

    I., & Sunyaev, R

    Shakura, N. I., & Sunyaev, R. A. (1973). Black holes in binary systems. Observational appearance. Astronomy and Astrophysics, 24, 337-355

    1973

  30. [30]

    Abdalla, E. et al. Cosmology intertwined: A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies. Journal of High Energy Astrophysics 34 (2022) 49211, arXiv:2203.06142 [astro-ph.CO]

    work page internal anchor Pith review Pith/arXiv arXiv 2022

  31. [31]

    The Planck Collaboration, Planck 2018 results. VI. Cosmological parameters Astronomy and Astrophysics, 641, A6 (2020)

    2018

  32. [32]

    Argüelles, C. A. et al. Dark matter decay to neutrinos Physical Review D , 108, 123021, (2023) – 16 –

    2023