New Exclusion Limits for the Search of Scalar and Pseudoscalar Axion-Like Particles from "Light Shining Through a Wall"

TL;DR

This paper reports new exclusion limits for axion-like particles from a light shining through a wall experiment, significantly improving constraints on their photon coupling in the sub-eV mass range.

Contribution

It presents the most sensitive laboratory limits to date on axion-like particles using photon regeneration with a high magnetic field and laser power.

Findings

No photon regeneration detected, setting new upper limits.

Photon coupling constraints are less than 3.5×10⁻⁸ GeV⁻¹ for pseudo-scalar ALPs.

Constraints are established at 95% confidence level.

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 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 $3.5\cdot 10^{-8}$ GeV$^{-1}$ and $3.2\cdot 10^{-8}$ GeV$^{-1}$, respectively, at 95% Confidence Level.