Dark energy in light of recent DESI BAO and Hubble tension

TL;DR

Recent DESI BAO data suggest evolving dark energy, but when combined with other datasets and considering Hubble tension resolutions, the standard cosmological constant remains consistent within 2σ, urging caution in claiming its exclusion.

Contribution

This study analyzes the impact of recent DESI BAO measurements on dark energy models within Hubble-tension-free cosmologies, highlighting the continued viability of the cosmological constant.

Findings

DESI data slightly favor evolving dark energy but remain consistent with a cosmological constant.

Hubble tension resolutions tend to reduce the preference for evolving dark energy.

Best-fit Hubble constant increases with DESI data without worsening the S8 tension.

Abstract

Recently, Dark Energy Spectroscopic Instrument (DESI) collaboration based on their first year data has reported a $\gtrsim 3\sigma$ evidence for an evolving dark energy (DE) against the cosmological constant (CC), so the standard $\Lambda$CDM model. However, it is necessary to access the impact of DESI data on the state equation $w_0$-$w_a$ of DE in the Hubble-tension-free cosmologies, where $w_0$ and $w_a$ is the parameters of state equation of DE. In this paper, using recent DESI BAO measurements combined with Planck CMB and Pantheon Plus dataset, we perform the Monte Carlo Markov Chain (MCMC) analysis for the $w_0w_a$CDM model with possible pre-recombination resolutions of the Hubble tension. It is found that though $w_0>-1$ and $w_a<0$ are still preferred, the CC is also $<2\sigma$ consistent, while the bestfit Hubble constant $H_0$ are higher than those with pre-DESI BAO data but without the further exacerbation of $S_8$ tension. According to our results, the resolutions of Hubble tension are likely to suppress the \textit{preference} of DESI for the evolving DE, thus the claim of ruling out the CC needs to be more cautious regarding not only the recent observational data but also the cosmological tensions.