  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 m_a <~ 0.02 eV. This result is the best
experimental limit over a broad range of axion masses and for m_a <~ 0.02 eV
also supersedes the previous limit derived from energy-loss arguments on
globular-cluster stars.
