2021/02/28 by Leo WH Fung, Lingfeng Li, Tao Liu +3 · 1 citation
Physics and Astronomy · #hep-ph #astro-ph.CO #hep-th
paper · pdf · doi:10.1088/1475-7516/2021/08/057
published as JCAP 08 (2021) 057 · 52 pages, 8 figures. Matches the published version in JCAP
arxiv created 2021/09/03 · arxiv updated 2021/09/06
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 \rm eV and decay constant fa ∼ 1017 - 1018 \rm GeV, to achieve this goal. The axion initial value a\rm ini yields an initial Δv\rm ini/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 ∼ 10-22 eV) in the fuzzy dark matter model to the axi-Higgs model allows bigger Δv\rm rec and ωa to address the Hubble and S8/σ8 tensions simultaneously. The model predicts that Δv may be detected by the spectral measurements of quasars, while its oscillation may be observed in the atomic clock measurements.