Key points are not available for this paper at this time.
We have searched for solar axions or similar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup with improved conditions in all detectors. From the absence of excess X-rays when the magnet was pointing to the Sun, we set an upper limit on the axion-photon coupling of 8. 8 x 10^-11 GeV^-1 at 95% CL for mₐ <~ 0. 02 eV. This result is the best experimental limit over a broad range of axion masses and for mₐ <~ 0. 02 eV also supersedes the previous limit derived from energy-loss arguments on globular-cluster stars.
Andriamonje et al. (Tue,) studied this question.