Dark energy in light of recent DESI BAO and Hubble tension

Understand

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.