Pith. sign in

REVIEW 2 major objections 2 minor 2 cited by

Combined DES and DESI data find no evidence for momentum exchange between dark matter and dark energy.

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 →

Challenge this review Download PDF Read on arXiv ↗

T0 review · grok-4.3

2026-05-16 20:43 UTC

load-bearing objection Adding DES Y3 photometry to DESI DR2 BAO plus SN and CMB tightens bounds on the dark scattering parameter but leaves the zero result dependent on clean cross-probe covariance. the 2 major comments →

arxiv 2512.17684 v2 submitted 2025-12-19 astro-ph.CO

Evolving and interacting dark energy: photometric and spectroscopic synergy with DES Y3 and DESI DR2

M. Tsedrik , B. Bose This is my paper
classification astro-ph.CO
keywords interacting dark energydark scatteringCPL parametrizationDES Y3DESI DR2cosmological constraintsdark energy equation of statestructure growth
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 dark matter and dark energy exchange momentum in addition to a time-varying dark energy equation of state. It combines two-point correlation functions from DES Year 3 photometry with baryon acoustic oscillations from DESI, supernovae distances, and CMB measurements. The interaction strength is found consistent with zero in every data combination examined. The simpler evolving dark energy model without interaction is statistically preferred over the interacting case.

Core claim

In the Dark Scattering scenario with CPL parametrization, the dark-sector interaction parameter A_ds remains consistent with zero for all data sets. The CPL model provides a better statistical fit than DS. Full combination yields w0 = -0.76 ± 0.06 and wa = -0.77+0.23-0.20 for CPL, while DS gives w0 = -0.79+0.05-0.06, wa = -0.56+0.24-0.15 and A_ds = 9.8+2.8-9.5 bn/GeV. Adding DES photometric information raises the figure of merit on (w0, wa) by roughly 12 percent for CPL and 25 percent for DS. Neither model shows an S8 discrepancy between low- and high-redshift probes.

What carries the argument

Dark Scattering (DS) model of pure momentum exchange between dark matter and dark energy, paired with the Chevallier-Polarski-Linder (CPL) parametrization of the dark energy equation of state, constrained through DES Y3 two-point functions and DESI BAO.

Load-bearing premise

The combined photometric and spectroscopic data sets contain no unaccounted systematics or selection effects that would bias the constraints on the interaction parameter or the dark energy equation-of-state parameters.

What would settle it

A future analysis of similar data finding the interaction parameter A_ds different from zero at greater than 3-sigma significance would falsify the claim that it is consistent with zero.

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

If this is right

  • DES photometric data improves the figure of merit on (w0, wa) by 12 percent for CPL and 25 percent for DS over DESI plus supernovae plus CMB alone.
  • CPL provides a statistically better fit than the interacting DS model for the chosen probes.
  • No S8 discrepancy appears between low-redshift and high-redshift measurements in either model.
  • The results give the tightest pre-Euclid constraints on the DS scenario from a joint photometric-spectroscopic analysis.

Where Pith is reading between the lines

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

  • Synergies between photometric and spectroscopic surveys can be extended to test other late-time modifications of gravity or dark energy.
  • If the interaction parameter stays zero, standard time-varying dark energy without momentum exchange suffices for current observations.
  • The absence of S8 tension in these models suggests that additional data from upcoming surveys will either confirm consistency or reveal new tensions.

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 / 2 minor

Summary. The manuscript investigates the Dark Scattering (DS) interacting dark energy scenario with pure momentum exchange, combined with the Chevallier-Polarski-Linder (CPL) parametrization for the dark energy equation of state. Using three two-point correlation functions from DES Y3, BAO from DESI DR2, Type Ia supernovae from DES Y5, and Planck CMB data, the authors derive constraints on cosmological, DS, and CPL parameters. They report that the interaction parameter A_ds is consistent with zero for all data combinations, that CPL provides a statistically preferred fit over DS, and quote specific values (e.g., w0 = -0.79^{+0.05}_{-0.06}, wa = -0.56^{+0.24}_{-0.15}, A_ds = 9.8^{+2.8}_{-9.5} bn/GeV for the full combination). Inclusion of DES photometric data improves the (w0, wa) figure of merit by ~12% (CPL) and ~25% (DS) relative to DESI+SN+CMB alone, with no evidence found for an S8 discrepancy.

Significance. If the joint constraints are robust against cross-probe systematics, the work supplies the most stringent pre-Euclid bounds on DS models from combined photometric and spectroscopic probes, quantifies the synergy gain from DES Y3, and demonstrates consistency with no late-time growth suppression or S8 tension in these extensions.

major comments (2)
  1. [Data analysis / likelihood section] The construction and validation of the joint likelihood and covariance matrix for the combined DES Y3 photometric two-point functions and DESI spectroscopic BAO (detailed in the data-analysis section) are insufficiently specified. In particular, the marginalization over cross-probe systematics (galaxy bias, magnification, selection effects) and any residual covariance between the datasets is not quantified, which directly affects the reliability of the A_ds posterior being consistent with zero.
  2. [Results] The claimed ~25% FoM improvement on (w0, wa) from adding DES photometry in the DS model (reported in the results) lacks an explicit test (e.g., nuisance-parameter impact or split-sample consistency) showing that unmodeled offsets in effective bias or covariance are sub-dominant to the reported A_ds uncertainty of 9.8^{+2.8}_{-9.5} bn/GeV.
minor comments (2)
  1. [Abstract] The abstract states that CPL is 'statistically preferred' over DS; a quantitative Delta chi^2 or Bayes factor should be provided in the main text for transparency.
  2. [Introduction] Notation for the DS interaction parameter (A_ds in bn/GeV) should be cross-checked for consistency with prior literature in the introduction.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thorough review and valuable comments on our manuscript. We address each of the major comments below, providing clarifications and indicating the revisions we will implement to strengthen the presentation of our analysis.

read point-by-point responses

  1. Referee: The construction and validation of the joint likelihood and covariance matrix for the combined DES Y3 photometric two-point functions and DESI spectroscopic BAO (detailed in the data-analysis section) are insufficiently specified. In particular, the marginalization over cross-probe systematics (galaxy bias, magnification, selection effects) and any residual covariance between the datasets is not quantified, which directly affects the reliability of the A_ds posterior being consistent with zero.

    Authors: We agree that more explicit details on the joint likelihood would enhance the clarity of the manuscript. In the revised version, we will expand the data-analysis section to include a detailed description of how the combined covariance matrix is constructed, including the estimation of cross-probe covariances via mock simulations and the marginalization procedure over shared systematics such as galaxy bias, magnification, and selection effects. We note that the DES Y3 and DESI analyses individually marginalize over these parameters, and the joint fit assumes that residual covariances are negligible, as supported by prior combined photometric-spectroscopic studies. This revision will directly address the concern regarding the robustness of the A_ds posterior. revision: yes

  2. Referee: The claimed ~25% FoM improvement on (w0, wa) from adding DES photometry in the DS model (reported in the results) lacks an explicit test (e.g., nuisance-parameter impact or split-sample consistency) showing that unmodeled offsets in effective bias or covariance are sub-dominant to the reported A_ds uncertainty of 9.8^{+2.8}_{-9.5} bn/GeV.

    Authors: We acknowledge the value of an explicit validation test for the reported FoM improvement. Accordingly, we will add to the results section a new test that assesses the impact of nuisance parameters (such as effective galaxy bias) on the FoM and performs a split-sample consistency check on the DES photometric data. This will confirm that any potential unmodeled offsets are sub-dominant compared to the uncertainty on A_ds. While our current analysis already incorporates comprehensive marginalization over nuisance parameters, leading to the reported constraints, this addition will provide the requested explicit demonstration. revision: yes

Circularity Check

0 steps flagged

No significant circularity in the derivation chain

full rationale

The paper constrains the DS interaction parameter A_ds and CPL parameters w0, wa by performing a joint likelihood fit to independent external datasets (DES Y3 two-point correlation functions, DESI BAO, DES Y5 supernovae, and Planck CMB). The reported results (A_ds consistent with zero, CPL statistically preferred) are direct outputs of this data-driven parameter estimation. No step reduces a claimed prediction to a fitted input by construction, invokes a load-bearing self-citation, or imports uniqueness via prior author work; the derivation remains self-contained against external observational benchmarks.

Axiom & Free-Parameter Ledger

3 free parameters · 2 axioms · 0 invented entities

The analysis fits standard cosmological parameters plus model-specific extensions to external observational data; no new entities are postulated.

free parameters (3)
  • A_ds = 9.8^{+2.8}_{-9.5} bn/GeV
    Dark scattering interaction strength parameter fitted to the data
  • w0 = -0.79^{+0.05}_{-0.06}
    Present-day dark energy equation-of-state parameter
  • wa = -0.56^{+0.24}_{-0.15}
    Dark energy evolution parameter in CPL parametrization
axioms (2)
  • domain assumption Standard flat FLRW background cosmology with linear perturbations
    Underlying framework for deriving constraints on DS and CPL extensions
  • domain assumption Pure momentum exchange with no energy transfer in the DS model
    Core definition of the interacting dark energy scenario tested

pith-pipeline@v0.9.0 · 5649 in / 1565 out tokens · 70412 ms · 2026-05-16T20:43:28.491621+00:00 · methodology

0 comments
read the original abstract

We investigate the Dark Scattering (DS) interacting dark energy scenario, characterised by pure momentum exchange between dark matter and dark energy, combined with a time-dependent equation-of-state for dark energy described by the Chevallier-Polarski-Linder (CPL) parametrisation. This class of models is weakly constrained by CMB observations and can exhibit distinctive late-time suppression of structure growth. We derive constraints on cosmological, DS, and CPL parameters using three two-point correlation functions from the Dark Energy Survey Year 3 data, combined with baryon acoustic oscillation measurements from DESI, Type Ia supernovae from DES Year 5, and CMB data from Planck. We find the dark-sector interaction parameter $A_\mathrm{ds}$ to be consistent with zero for all data combinations, and that CPL provides a statistically preferred fit over DS for the selected probes. From the full data combination we obtain $w_0=-0.76 \pm 0.06, \, w_a=-0.77^{+0.23}_{-0.20}$ for CPL, and $w_0=-0.79^{+0.05}_{-0.06}, \, w_a=-0.56^{+0.24}_{-0.15}, \, (A_\mathrm{ds}=9.8^{+2.8}_{-9.5} \, \mathrm{bn/GeV})$ for DS. The inclusion of DES photometric information improves the Figure-of-Merit on $(w_0,w_a)$ by $\sim$12% for CPL and $\sim$25% for DS relative to DESI+SN+CMB alone. We find no evidence for an $S_8$ discrepancy between the low-$z$ and high-$z$ measurements in either model. These results provide the most stringent pre-Euclid constraints on DS from a combined photometric and spectroscopic analysis.

Figures

Figures reproduced from arXiv: 2512.17684 by B. Bose, M. Tsedrik.

Figure 1
Figure 1. Figure 1: Linear growth factor in DS with respect to ΛCDM today, overlayed with official DESI results for evolving dark energy without interaction (specific combinations of cosmological probes are shown in the legend). The reddish region on the heatmap denotes enhancement of structure growth with respect to ΛCDM, while the blueish region denotes suppression. Grey dashed lines mark the ΛCDM-limit for the dark energy … view at source ↗
Figure 2
Figure 2. Figure 2: Quantiles of the relative accuracy of our DS emulator on 6 · 104 testing samples. The dashed grey line denotes the 1% accuracy. been partly remedied with a recent patch to the code. The emulator can be found here ‡. In [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Dark energy results for different data selections, specified in the legend of the lower panels. CPL constraints are shown in dark red, DS constraints are shown in blue. All contours shown contain 68% and 95% of the posterior probability. Dashed yellow regions denote priors in DS: w0 + wa < −1/2 for the existence of a growing solution of the linearised growth equation and 0 < ξ < 150 [bn/GeV]. w0 −2 −1 0 w … view at source ↗
Figure 4
Figure 4. Figure 4: CPL: constraints without (in blue) and with (in dark red) photometric information from DES. Grey dashed lines denote ΛCDM limit in equation-of-state parameters. Grey stripe denotes constraints from Planck 2018 without lensing for ΛCDM (Planck Collaboration et al. 2020). tional, yet less significant, difference between the DESI and our results is the choice of CMB likelihoods. We further compare DS and CPL … view at source ↗
Figure 6
Figure 6. Figure 6: The Bayes factor: ln B = ln ZCPL−ln ZDS. Er￾rorbars correspond to 68% c.l. provided by the samplers. The shaded regions denote the Jeffreys’ scale thresholds for evidence interpretation, i.e. significance of CPL being better supported by data than DS: 0 < ln B < 1 (incon￾clusive), 1 < ln B < 2.5 (weak), 2.5 < ln B < 5 (moder￾ate), and ln B > 5 (strong). The filled stars denote DS with the evolving equation… view at source ↗
Figure 1
Figure 1. Figure 1: Dark energy results with the full combination of cosmological probes – DES+DESI+SN+CMB – for different models, specified in the legend. CPL constraints are shown in black, DS constraints with (w0wa) are shown in blue and DS with the constant equation-of-state in dark red. All contours shown contain 68% and 95% of the posterior probability. Dashed yellow regions denote priors in DS: w0 + wa < −1/2 for the e… view at source ↗

discussion (0)

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

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Forward citations

Cited by 2 Pith papers

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

  1. Disentangling Similarity and Relatedness in Topic Models

    cs.CL 2026-03 conditional novelty 7.0

    Topic models lie on a spectrum from thematic-relatedness-rich to similarity-rich, and that position predicts which downstream tasks they handle well.

  2. Disentangling Similarity and Relatedness in Topic Models

    cs.CL 2026-03 unverdicted novelty 6.0

    Topic-model families occupy distinct positions on a similarity–relatedness plane, and those positions predict which downstream tasks they help or hurt.

Reference graph

Works this paper leans on

1 extracted references · 1 canonical work pages · cited by 1 Pith paper · 1 internal anchor

  1. [1]

    Abbott T. M. C., et al., 2019, Phys. Rev. D, 99, 123505 Abbott T. M. C., et al., 2022a, Phys. Rev. D, 105, 023520 Abbott T. M. C., et al., 2022b, Phys. Rev. D, 105, 023520 Abbott T. M. C., et al., 2023, Phys. Rev. D, 107, 083504 Abbott T. M. C., et al., 2024, Astrophys. J. Lett., 973, L14 Abdul Karim M., et al., 2025a, DESI DR2 Results II: Measurements of...

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1016/j.dark.2025.101965 2019