Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8186497 | Physics Letters B | 2018 | 4 Pages |
Abstract
If the Peccei-Quinn symmetry is already broken during inflation, the decay constant Fa of the axion can be in a wide region from 1011GeV to 1018GeV for the axion being the dominant dark matter. In this case, however, the axion causes the serious cosmological problem, isocurvature perturbation problem, which severely constrains the Hubble parameter during inflation. The constraint is relaxed when Peccei-Quinn scalar field takes a large value â¼Mp (Planck scale) during inflation. In this letter, we point out that the allowed region of the decay constant Fa is reduced to a rather narrow region for a given tensor-to-scalar ratio r when Peccei-Quinn scalar field takes â¼Mp during inflation. For example, if the ratio r is determined as râ³10â3 in future measurements, we can predict Faâ(0.1-1.4)Ã1012GeV for domain wall number NDW=6.
Related Topics
Physical Sciences and Engineering
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Nuclear and High Energy Physics
Authors
Masahiro Kawasaki, Eisuke Sonomoto, Tsutomu T. Yanagida,