Axions as Hot and Cold Dark Matter

Abstract

The presence of a hot dark matter component has been hinted at 3 sigma by a combination of the results from different cosmological observations. We examine a possibility that pseudo Nambu-Goldstone bosons account for both hot and cold dark matter components. We show that the QCD axions can do the job for the axion decay constant f_a < O(10^10) GeV, if they are produced by the saxion decay and the domain wall annihilation. We also investigate the cases of thermal QCD axions, pseudo Nambu-Goldstone bosons coupled to the standard model sector through the Higgs portal, and axions produced by modulus decay.

24 pages, 1 figure

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Cited by in corpus (15)

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• Blue Tensor Spectrum from Particle Production during Inflation
• The 7 keV axion dark matter and the X-ray line signal
• Observational implications of mattergenesis during inflation
• Anomaly-free flavor models for Nambu-Goldstone bosons and the 3.5 keV X-ray line signal
• Running Spectral Index from Large-field Inflation with Modulations Revisited
• Axion monodromy inflation with multi-natural modulations
• How Late can the Dark Matter form in our universe?
• Constraining SUSY with Heavy Scalars -- using the CMB
• Non-thermal Hot Dark Matter from Inflaton/Moduli Decay: The Momentum Distribution and Relaxing the Cosmological Mass Bound
• Daughters mimic sterile neutrinos (almost!) perfectly
• CDM/baryon isocurvature perturbations in a sneutrino curvaton model
• Non-thermal Axion Dark Radiation and Constraints
• Spatially open Friedmann--Robertson--Walker Universe fueled with interacting sources
• The Continuous Tower of Scalar Fields as a System of Interacting Dark Matter -- Dark Energy