Cosmology of the DFSZ axino
  We study the cosmological impact of the supersymmetric DFSZ axion model.
Extending recent works, we first provide a comprehensive analysis of thermal
production of the DFSZ axino considering all the possible scattering, decay and
inverse decay processes depending on various mass parameters and the reheat
temperature. Although it is hard for the DFSZ axino to be in thermal
equilibrium, its coupling is still large enough to generate huge axino
population which can turn into overabundant neutralino density. We examine the
neutralino parameter space to identify the dark matter property depending on
the Peccei-Quinn scale. As the Peccei-Quinn scale becomes higher resulting in
longer axino lifetime, the neutralino dark matter appears in a lighter
Higgsino-like LSP region or a more restricted Bino-like LSP region allowing a
resonant annihilation through a CP-odd Higgs boson to meet stronger
reannihilation.
