Physics beyond the Standard Model predicts the possible existence of new particles that can be searched at the low energy frontier in the sub-eV range. The OSQAR photon regeneration experiment looks for Light Shining through a Wall from the quantum o
scillation of optical photons into Weakly Interacting Sub-eV Particles, such as axion or Axion-Like Particles (ALPs), in a 9 T transverse magnetic field over the unprecedented length of $2 times 14.3$ m. In 2014, this experiment has been run with an outstanding sensitivity, using an 18.5 W continuous wave laser emitting in the green at the single wavelength of 532 nm. No regenerated photons have been detected after the wall, pushing the limits for the existence of axions and ALPs down to an unprecedented level for such a type of laboratory experiment. The di-photon couplings of possible pseudo-scalar and scalar ALPs can be constrained in the nearly massless limit to be less than $3.5cdot 10^{-8}$ GeV$^{-1}$ and $3.2cdot 10^{-8}$ GeV$^{-1}$, respectively, at 95% Confidence Level.
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 ris
e 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.
