Improved Planck Constraints on Axionlike Early Dark Energy as a Resolution of the Hubble Tension.

• DOI: 10.48550/arxiv.2311.00524
• Publication Date: 2024-05-28
• Authors: George Efstathiou; Erik Rosenberg; Vivian Poulin
• Keywords: High Energy Physics - Phenomenology; Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Phenomenology (hep-ph); FOS: Physical sciences; Astrophysics - Cosmology and Nongalactic Astrophysics

Axion-like early dark energy (EDE) as an extension to $Λ$CDM has been proposed as a possible solution to the 'Hubble tension'. We revisit this model using a new cosmic microwave background (CMB) temperature and polarization likelihood constructed from the {\it Planck} NPIPE data release. In a Bayesian analysis, we find that the maximum fractional contribution of EDE to the total energy density is $f_{\rm EDE} < 0.061$ (without SH0ES) over the redshift range $z\in[10^3,10^4]$ and that the Hubble constant is constrained to lie within the range $ 66.9 < H_0 < 69.5$ km/s/Mpc (both at 95 \% C.L.). The data therefore favour a model close to $Λ$CDM, leaving a residual tension of $3.7σ$ with the SH$0$ES Cepheid-based measurement of $H_0$. A comparison with the likelihood profile shows that our conclusions are robust to prior-volume effects. Our new CMB likelihood provides no evidence in favour of a significant EDE component.<br/>4 pages, 3 figures, comments welcome<br/>