The experimental challenge of detecting solar axion-like particles to
  test cosmological ALP-photon oscillation hypothesis
  We consider possible experimental tests of recent hypotheses suggesting that
TeV photons survive the pair production interaction with extragalactic
background light over cosmological distances by converting to axion-like
particles (ALPs) in galactic magnetic fields. We show that proposed giant
ultra-low background scintillation detectors will even have a difficult time
reaching the present CAST sensitivity, which is one to two orders of magnitude
less sensitive than necessary for a meaningful test of the ALP-photon
oscillation hypothesis. Potential alternative tests are briefly discussed.
