Latest Results of the OSQAR Photon Regeneration Experiment for   Axion-Like Particle Search
  The OSQAR photon regeneration experiment searches for pseudoscalar and scalar axion-like particles by the method of "Light Shining Through a Wall", based on the assumption that these weakly interacting sub-eV particles couple to two photons to give rise to quantum oscillations with optical photons in strong magnetic field. No excess of events has been observed, which constrains the di-photon coupling strength of both pseudoscalar and scalar particles down to $5.7 \cdot 10^{-8}$ GeV$^{-1}$ in the massless limit. This result is the most stringent constraint on the di-photon coupling strength ever achieved in laboratory experiments. 
R. Ballou, G. Deferne, L. Duvillaret, M. Finger, Jr., M. Finger, L.   Flekova, J. Hosek, T. Husek, V. Jary, R. Jost, M. Kral...
hep-ex astro-ph.CO hep-ph physics.ins-det