Preference for evolving dark energy in light of the galaxy bispectrum

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Auteurs principaux: Lu, Zhiyu, Simon, Théo, Zhang, Pierre
Format: Preprint
Publié: 2025
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author Lu, Zhiyu
Simon, Théo
Zhang, Pierre
author_facet Lu, Zhiyu
Simon, Théo
Zhang, Pierre
contents We analyse pre-DESI clustering data using a dark energy equation of state $w(z)$ parametrised by $(w_0, w_a)$, finding a $2.8-3.9σ$ preference for evolving dark energy over the cosmological constant $Λ$ when combined with cosmic microwave background data from Planck and supernova data from Pantheon+, Union3, or DESY5. Our constraints, consistent with DESI Y1 results, are derived from the power spectrum and bispectrum of SDSS/BOSS galaxies using the Effective Field Theory of Large Scale Structure (EFTofLSS) at one loop. The evidence remains robust across analysis variations but disappears without the one-loop bispectrum. When combining DESI baryon acoustic oscillations with BOSS full-shape data, while marginalising over the sound horizon in the latter to prevent unaccounted correlations, the significance increases to $3.7-4.4σ$, depending on the supernova dataset. Using a data-driven reconstruction of $w(z)$, we show that the evidence arises from deviations from $Λ$ at multiple redshifts. In addition, our findings are interpreted within the Effective Field Theory of Dark Energy (EFTofDE), from which we explicitly track the non-standard time evolution in EFTofLSS predictions. For perturbatively stable theories in the $w < -1$ regime, the evidence persists in the clustering limit $(c_s^2 \rightarrow 0)$ when higher-derivative corrections are present, as well as in the quasi-static limit $(c_s^2 \rightarrow 1)$ when additional EFTofDE parameters are considered.
format Preprint
id arxiv_https___arxiv_org_abs_2503_04602
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Preference for evolving dark energy in light of the galaxy bispectrum
Lu, Zhiyu
Simon, Théo
Zhang, Pierre
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
We analyse pre-DESI clustering data using a dark energy equation of state $w(z)$ parametrised by $(w_0, w_a)$, finding a $2.8-3.9σ$ preference for evolving dark energy over the cosmological constant $Λ$ when combined with cosmic microwave background data from Planck and supernova data from Pantheon+, Union3, or DESY5. Our constraints, consistent with DESI Y1 results, are derived from the power spectrum and bispectrum of SDSS/BOSS galaxies using the Effective Field Theory of Large Scale Structure (EFTofLSS) at one loop. The evidence remains robust across analysis variations but disappears without the one-loop bispectrum. When combining DESI baryon acoustic oscillations with BOSS full-shape data, while marginalising over the sound horizon in the latter to prevent unaccounted correlations, the significance increases to $3.7-4.4σ$, depending on the supernova dataset. Using a data-driven reconstruction of $w(z)$, we show that the evidence arises from deviations from $Λ$ at multiple redshifts. In addition, our findings are interpreted within the Effective Field Theory of Dark Energy (EFTofDE), from which we explicitly track the non-standard time evolution in EFTofLSS predictions. For perturbatively stable theories in the $w < -1$ regime, the evidence persists in the clustering limit $(c_s^2 \rightarrow 0)$ when higher-derivative corrections are present, as well as in the quasi-static limit $(c_s^2 \rightarrow 1)$ when additional EFTofDE parameters are considered.
title Preference for evolving dark energy in light of the galaxy bispectrum
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2503.04602