PREPRINT
55FB47AA-8FE5-48DF-837B-7A26BC1E3477

A grounded perspective on New Early Dark Energy using ACT, SPT, and BICEP/Keck

Juan S. Cruz, Florian Niedermann, Martin S. Sloth
arXiv:2209.02708

Submitted on 6 September 2022

Abstract

We examine further the ability of the New Early Dark Energy model (NEDE) to resolve the current tension between the Cosmic Microwave Background (CMB) and local measurements of ${H}_{0}$ and the consequences for inflation. We perform new Bayesian analyses, including the current datasets from the ground-based CMB telescopes Atacama Cosmology Telescope (ACT), the South Pole Telescope (SPT), and the BICEP/Keck telescopes, employing an updated likelihood for the local measurements coming from the S${H}_{0}$ES collaboration. Using the S${H}_{0}$ES prior on ${H}_{0}$, the combined analysis with Baryonic Acoustic Oscillations (BAO), Pantheon, Planck and ACT improves the best-fit by $\mathrm{\Delta }{\chi }^{2}=-15.9$ with respect to $\mathrm{\Lambda }$CDM, favors a non-zero fractional contribution of NEDE, ${f}_{\mathrm{N}\mathrm{E}\mathrm{D}\mathrm{E}}>0$, by $4.8\sigma$, and gives a best-fit value for the Hubble constant of ${H}_{0}=72.09$ km/s/Mpc (mean ${71.48}_{-0.81}^{+0.79}$ with $68\mathrm{%}$ C.L.). A similar analysis using SPT instead of ACT yields consistent results with a $\mathrm{\Delta }{\chi }^{2}=-23.1$ over $\mathrm{\Lambda }$CDM, a preference for non-zero ${f}_{\mathrm{N}\mathrm{E}\mathrm{D}\mathrm{E}}$ of $4.7\sigma$ and a best-fit value of ${H}_{0}=71.77$ km/s/Mpc (mean ${71.43}_{-0.84}^{+0.84}$ with $68\mathrm{%}$ C.L.). We also provide the constraints on the inflation parameters $r$ and ${n}_{s}$ coming from NEDE, including the BICEP/Keck 2018 data, and show that the allowed upper value on the tensor-scalar ratio is consistent with the $\mathrm{\Lambda }$CDM bound, but, as also originally found, with a more blue scalar spectrum implying that the simplest curvaton model is now favored over the Starobinsky inflation model.

Preprint

Comment: 32 pages, 10 figures, 14 tables

Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics; High Energy Physics - Phenomenology; High Energy Physics - Theory