Hot New Early Dark Energy: Dark Radiation Matter Decoupling

arXiv:2508.03795 · astro-ph.CO, hep-ph, hep-th · Submitted 2025-08-05 · Read on arXiv

astro-ph.CO, hep-ph, hep-th

Submitted: 2025-08-05

Updated: 2026-09-10

Comments: 38 pages, 8 figures, 2 tables; code available at https://github.com/NEDE-Cosmo/DRMD-CLASS; matches version published in PRD

Journal ref: Phys.Rev.D 114 (2026) 4, 043532

DOI: 10.1103/787w-dpbz

Code: https://github.com/NEDE-Cosmo/DRMD-CLASS

License: http://creativecommons.org/licenses/by/4.0/

The gist: We present a microscopic model of the dark sector that resolves the Hubble tension within standard current data sets (Planck 2018, Pantheon+ and DESI DR2 BAO) based on well-known fundamental

Terminology

Abstract

We present a microscopic model of the dark sector that resolves the Hubble tension within standard current data sets (Planck 2018, Pantheon+ and DESI DR2 BAO) based on well-known fundamental principles, gauge symmetry and spontaneous symmetry breaking. It builds on the Hot New Early Dark Energy (Hot NEDE) setup, featuring a dark SU(N) gauge symmetry broken to SU(N-1) in a supercooled phase transition that creates a thermal bath of self-interacting dark radiation in the epoch between Big Bang Nucleosynthesis and recombination. Adding a fermion multiplet charged under the gauge symmetry provides a naturally stable component of dark matter that interacts with dark radiation. Spontaneous symmetry breaking predicts a decoupling of this interaction once the dark sector cools down, that we refer to as dark radiation matter decoupling (DRMD). We also provide a simplified DRMD model that captures the essential features of the full theory while retaining additional falsifiable predictions. Using the data sets stated above, we find agreement with the SH 0 ES determination of H 0 at the 1.4 σ level, compared to a 5.7 σ tension in Λ CDM, thereby providing a resolution of the Hubble tension.

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