New exclusion limits on scalar and pseudoscalar axionlike particles from light shining through a wall
Abstract
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 oscillation of optical photons into "weakly interacting subeV particles," such as axion or axionlike particles (ALPs) in a 9 T transverse magnetic field over a length of 2 x 14.3 m.
In 2014, this experiment was 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 type of laboratory experiment.
The diphoton couplings of possible pseudoscalar and scalar ALPs can be constrained in the nearly massless limit to be less than 3.5 x 10(-8) GeV-1 and 3.2 x 10(-8) GeV-1, respectively, at 95% confidence level.