## 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 SH _{0}ES collaboration. Using the SH _{0}ES prior on H _{0}, the combined analysis with Baryonic Acoustic Oscillations (BAO), Pantheon, Planck and ACT improves the best-fit by Δχ ^{2} = -15.9 with respect to ΛCDM, favors a non-zero fractional contribution of NEDE, f _{NEDE} > 0, by 4.8σ, and gives a best-fit value for the Hubble constant of H _{0} = 72.09 km/s/Mpc (mean 71.49 ± 0.82 with 68% C.L.). A similar analysis using SPT instead of ACT yields consistent results with a Δχ ^{2} = -23.1 over ΛCDM, a preference for non-zero f _{NEDE} of 4.7σ and a best-fit value of H _{0} = 71.77 km/s/Mpc (mean 71.43 ± 0.85 with 68% 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 ΛCDM 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.

Original language | English |
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Article number | 041 |

Journal | Journal of Cosmology and Astroparticle Physics |

Volume | 2023 |

Issue number | 2 |

Number of pages | 38 |

ISSN | 1475-7516 |

DOIs | |

Publication status | Published - 22. Feb 2023 |

### Bibliographical note

32 pages, 10 figures, 14 tables## Keywords

- astro-ph.CO
- hep-ph
- hep-th
- cosmological parameters from CMBR
- dark energy theory
- cosmology of theories beyond the SM
- cosmological phase transitions