Axi-Higgs cosmology

• Published in: Journal of cosmology and astroparticle physics 2021-08, Vol.2021 (8), p.57
• Main Authors: Fung, Leo W.H., Li, Lingfeng, Liu, Tao, Luu, Hoang Nhan, Qiu, Yu-Cheng, Tye, S.-H. Henry
• Format: Article
• Language: English
• Subjects: Atomic clocks; axions; big bang nucleosynthesis; Birefringence; Cosmic microwave background; Cosmology; cosmology of theories beyond the SM; Dark matter; De Broglie wavelengths; Decay rate; Density; Quasars; recombination; Universe
• ISSN: 1475-7516; 1475-7516
• DOI: 10.1088/1475-7516/2021/08/057

If the electroweak Higgs vacuum expectation value v in early universe is ∼ 1 % higher than its present value v0=246 GeV, the 7Li puzzle in BBN and the CMB/ΛCDM tension with late-universe measurements on Hubble parameter are mitigated. We propose a model of an axion coupled to the Higgs field, named “axi-Higgs”, with its mass ma ∼ 10-30 - 10-29 eV and decay constant fa ∼ 1017 - 1018 GeV, to achieve this goal. The axion initial value aini yields an initial Δ vini/v0 ∼ 0.01 throughout the BBN-recombination epoch and a percent level contribution to the total matter density today. Because of its very large de Broglie wavelength, this axion matter density ωa suppresses the matter power spectrum, alleviating the CMB/ΛCDM S8/σ8 tension with the weak-lensing data. It also explains the recently reported isotropic cosmic birefringence by its coupling with photons. Adding the axion (m ∼ 10-22eV) in the fuzzy dark matter model to the axi-Higgs model allows bigger Δ vrec and ωa to address the Hubble and S8/σ8 tensions simultaneously. The model predicts that Δ v may be detected by the spectral measurements of quasars, while its oscillation may be observed in the atomic clock measurements.