Abstract
If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10-6 eV. This bound can be evaded if the Universe underwent inflation after PQ symmetry breaking and if the observable Universe happens to be a region where the initial axion angle was atypically small, 1[ma/(10-6 eV]0.59.] We show consideration of fluctuations induced during inflation severely constrains the latter alternative.
Original language | English (US) |
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Pages (from-to) | 5-8 |
Number of pages | 4 |
Journal | Physical Review Letters |
Volume | 66 |
Issue number | 1 |
DOIs | |
State | Published - 1991 |
Externally published | Yes |
ASJC Scopus subject areas
- General Physics and Astronomy