Axion baryogenesis puts a new spin on the Hubble tension

• DOI: 10.48550/arxiv.2405.12268
• Publication Date: 2024-05-20
• Authors: Raymond T. Co; Nicolas Fernandez; Akshay Ghalsasi; Keisuke Harigaya; Jessie Shelton
• Keywords: Tension (geology)

We show that a rotating axion field makes transition from matter-like equation of state to kination-like around the epoch recombination can significantly ameliorate Hubble tension, i.e., discrepancy between determinations present-day expansion rate $H_0$ observations cosmic microwave background on one hand and Type Ia supernovae other. consider specific, UV-complete model such find it relax tension without exacerbating tensions in other cosmological parameters, particular amplitude matter fluctuations $S_8$. subsequently demonstrate how this also generate baryon asymmetry our universe, by introducing coupling right-handed neutrinos. This baryogenesis predicts heavy neutral leptons are most naturally within reach future lepton colliders, but finely-tuned regions parameter space may be accessible at high-luminosity LHC beam dump experiment SHiP.