Hot new early dark energy: Dark radiation matter decoupling

We present a microscopic model of the dark sector that resolves the Hubble tension within standard current datasets (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 S U ( N ) gauge symmetry broken to S U ( 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 datasets 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.