English

Does DESI 2024 Confirm $\Lambda$CDM?

Cosmology and Nongalactic Astrophysics 2025-07-29 v3 General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory

Abstract

We demonstrate that a 2σ\sim 2 \sigma discrepancy with the Planck-Λ\LambdaCDM cosmology in DESI Luminous Red Galaxy (LRG) data in the redshift range 0.4<z<0.60.4 < z < 0.6 with effective redshift zeff=0.51z_{\textrm{eff}} = 0.51 translates into an unexpectedly large Ωm\Omega_m value, Ωm=0.670.17+0.18\Omega_m = 0.67^{+0.18}_{-0.17}. We independently confirm that this anomaly drives the preference for w0>1w_0 > -1 in DESI data \textit{alone} confronted to the w0waw_0 w_aCDM model. Given that LRG data at zeff=0.51z_{\textrm{eff}} = 0.51 is at odds with Type Ia supernovae in overlapping redshifts, we expect that this anomaly will decrease in statistical significance with future DESI data releases leaving an increasing Ωm\Omega_m trend with effective redshift at higher redshifts. We estimate the current significance of the latter in DESI data at 1.8σ\sim 1.8 \sigma and comment on how it dovetails with independent observations. It is imperative to understand what makes DESI LRG data at zeff=0.51z_{\textrm{eff}} = 0.51 an outlier when it comes to Ωm\Omega_m determinations.

Cite

@article{arxiv.2404.08633,
  title  = {Does DESI 2024 Confirm $\Lambda$CDM?},
  author = {Eoin Ó Colgáin and Maria Giovanna Dainotti and Salvatore Capozziello and Saeed Pourojaghi and M. M. Sheikh-Jabbari and Dejan Stojkovic},
  journal= {arXiv preprint arXiv:2404.08633},
  year   = {2025}
}

Comments

5 pages, 3 figures; v2 comments added, references updated; v3 to appear in JHEAP

R2 v1 2026-06-28T15:52:46.057Z