Relaxing the cosmological moduli problem by low-scale inflation

Shu Yu Ho, Fuminobu Takahashi, Wen Yin

研究成果: Article査読

17 被引用数 (Scopus)


We show that the cosmological abundance of string axions is much smaller than naive estimates if the Hubble scale of inflation, H inf , is sufficiently low (but can still be much higher than the axion masses) and if the inflation lasts sufficiently long. The reason is that the initial misalignment angles of the string axions follow the Bunch-Davies distribution peaked at the potential minima. As a result, the cosmological moduli problem induced by the string axions can be significantly relaxed by low-scale inflation, and astrophysical and cosmological bounds are satisfied over a wide range of the mass without any fine-tuning of the initial misalignment angles. Specifically, the axion with its decay constant f ϕ = 10 16 GeV satisfies the bounds over 10 −18 eV ≲ m ϕ ≲ 10 TeV for H inf ≲ 10 keV-10 6 GeV. We also discuss cases with multiple axions and the QCD axion.

ジャーナルJournal of High Energy Physics
出版ステータスPublished - 2019 4 1

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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