Further support for $S_8$ increasing with effective redshift

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Main Authors: Akarsu, Özgür, Colgáin, Eoin Ó, Sen, Anjan A., Sheikh-Jabbari, M. M.
Format: Preprint
Published: 2024
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author Akarsu, Özgür
Colgáin, Eoin Ó
Sen, Anjan A.
Sheikh-Jabbari, M. M.
author_facet Akarsu, Özgür
Colgáin, Eoin Ó
Sen, Anjan A.
Sheikh-Jabbari, M. M.
contents In Adil et al. 2023, we reported an increasing trend in $S_8$ with effective redshift $z_{\textrm{eff}}$ based on $f σ_8(z)$ constraints over the redshift range $0 \lesssim z \lesssim 2$, and predicted that this trend would be observable in independent datasets. Recently, the studies by Artis et al. and the ACT+DESI collaboration appeared, presenting data that aligns with the expected trends. In this letter, we quantify the statistical significance of the increasing $S_8$ trends in recent studies by fitting a linear model to estimate the slope $Δ\,S_8/Δ\, z_{\textrm{eff}}$, and comparing the results to mock simulations. We find probabilities of $p = 0.0163$ and $p = 0.01893$, corresponding to approximately $2.1σ$ for each dataset. Using Fisher's method to combine the independent probabilities, we obtained $p=0.0027$ ($2.8 σ$). When we incorporate our earlier findings, the combined statistical significance reaches between $3σ$ and $3.7σ$. Finally, we discuss how ``scatter" in $σ_8$/$S_8$ constraints from recent DESI full-shape galaxy clustering fits this picture at low statistical significance. This letter continues a series of studies initiated in 2020 that explore redshift-dependent $Λ$CDM parameters as an indication of a breakdown in the standard cosmological model.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23134
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Further support for $S_8$ increasing with effective redshift
Akarsu, Özgür
Colgáin, Eoin Ó
Sen, Anjan A.
Sheikh-Jabbari, M. M.
Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
High Energy Physics - Theory
In Adil et al. 2023, we reported an increasing trend in $S_8$ with effective redshift $z_{\textrm{eff}}$ based on $f σ_8(z)$ constraints over the redshift range $0 \lesssim z \lesssim 2$, and predicted that this trend would be observable in independent datasets. Recently, the studies by Artis et al. and the ACT+DESI collaboration appeared, presenting data that aligns with the expected trends. In this letter, we quantify the statistical significance of the increasing $S_8$ trends in recent studies by fitting a linear model to estimate the slope $Δ\,S_8/Δ\, z_{\textrm{eff}}$, and comparing the results to mock simulations. We find probabilities of $p = 0.0163$ and $p = 0.01893$, corresponding to approximately $2.1σ$ for each dataset. Using Fisher's method to combine the independent probabilities, we obtained $p=0.0027$ ($2.8 σ$). When we incorporate our earlier findings, the combined statistical significance reaches between $3σ$ and $3.7σ$. Finally, we discuss how ``scatter" in $σ_8$/$S_8$ constraints from recent DESI full-shape galaxy clustering fits this picture at low statistical significance. This letter continues a series of studies initiated in 2020 that explore redshift-dependent $Λ$CDM parameters as an indication of a breakdown in the standard cosmological model.
title Further support for $S_8$ increasing with effective redshift
topic Cosmology and Nongalactic Astrophysics
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2410.23134