Dark radiation and dark matter in supersymmetric axion models with high
  reheating temperature
  Recent studies of the cosmic microwave background, large scale structure, and
big bang nucleosynthesis (BBN) show trends towards extra radiation. Within the
framework of supersymmetric hadronic axion models, we explore two
high-reheating-temperature scenarios that can explain consistently extra
radiation and cold dark matter (CDM), with the latter residing either in
gravitinos or in axions. In the gravitino CDM case, axions from decays of
thermal saxions provide extra radiation already prior to BBN and decays of
axinos with a cosmologically required TeV-scale mass can produce extra entropy.
In the axion CDM case, cosmological constraints are respected with light
eV-scale axinos and weak-scale gravitinos that decay into axions and axinos.
These decays lead to late extra radiation which can coexist with the early
contributions from saxion decays. Recent results of the Planck satellite probe
extra radiation at late times and thereby both scenarios. Further tests are the
searches for axions at ADMX and for supersymmetric particles at the LHC.
