Resonant conversions of QCD axions into hidden axions and suppressed isocurvature perturbations

2014/11/17 by Naoya Kitajima, Fuminobu Takahashi · 3 citations
Physics and Astronomy · #Axion #Dark Matter and Cosmic Phenomena #Dark matter #Hidden sector #Inflation (cosmology) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #astro-ph.CO #hep-ph #hep-th

paper · pdf · doi:10.1088/1475-7516/2015/01/032

18 pages, 4 figures, v2: typos corrected, conclusions unchanged

arxiv created 2014/11/17 · openalex publication_date 2015/01/22 · arxiv updated 2015/06/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We study in detail MSW-like resonant conversions of QCD axions into hidden axions, including cases where the adiabaticity condition is only marginally satisfied, and where anharmonic effects are non-negligible. When the resonant conversion is efficient, the QCD axion abundance is suppressed by the hidden and QCD axion mass ratio. We find that, when the resonant conversion is incomplete due to a weak violation of the adiabaticity, the CDM isocurvature perturbations can be significantly suppressed, while non-Gaussianity of the isocurvature perturbations generically remain unsuppressed. The isocurvature bounds on the inflation scale can therefore be relaxed by the partial resonant conversion of the QCD axions into hidden axions.

Citations

• Light spinless particle coupled to photons
• Cosmological bounds on pseudo Nambu-Goldstone bosons
• The type IIB string axiverse and its low-energy phenomenology
• Planck2013 results. XVI. Cosmological parameters
• String axiverse

Cited by

• Axion isocurvature perturbations in low-scale models of hybrid inflation
• Level crossing between the QCD axion and an axionlike particle
• Axion Mixing in the String Axiverse