Dilution of Cosmological Axions by Entropy Production
Mar, 1990
20 pages
Published in:
- Nucl.Phys.B 346 (1990) 193-212
- Published: 1990
Report number:
- BA-90-10
Citations per year
Abstract: (Elsevier)
The usual cosmological bound on axions can be significantly relaxed if the universe experienced a period of entropy production between the time axions were produced and nucleosynthesis. We discuss a scenario in which a large amount of entropy is generated by decaying particles of mass 1–10 TeV. We find that nucleosynthesis constraints the decay lifetimes to be less than about 0.03 seconds. Using this limiting lifetime, we derive cosmological limits on the axion mass and find that m a ≳ 9 × 10 −8 eV if the axion density is dominated by radiation from strings. This limit is far from the limit m a ≲ 10 −3 based on supernova 1987A, thus showing clearly a case where axionic strings do not need to be inflated away. If the strings were inflated away, we can relax the axion mass bound to m a ≳ 5 × 10 −9 eV.- astrophysics: string
- postulated particle: axion
- entropy: production
- production: entropy
- mass: axion
- axion: mass
- scalar particle: lifetime
- light nucleus: production
- production: light nucleus
- density: axion
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