Laser experiments explore the hidden sector

TL;DR

Laser experiments like BMV and GammeV, originally designed to detect axion-like particles, can also constrain a broader class of hidden-sector particles, significantly improving existing bounds and providing new limits on minicharged particles.

Contribution

This paper demonstrates that laser light-shining-through-walls experiments can constrain various hidden-sector particles beyond axion-like particles, offering improved bounds and new constraints.

Findings

Experiments improve bounds on axion-like particles by a factor of two.

New constraints on minicharged particles with charges less than 3-4 x 10^(-7) times the electron charge.

Laboratory bounds are comparable to cosmological bounds from the CMB.

Abstract

Recently, the laser experiments BMV and GammeV, searching for light shining through walls, have published data and calculated new limits on the allowed masses and couplings for axion-like particles. In this note we point out that these experiments can serve to constrain a much wider variety of hidden-sector particles such as, e.g., minicharged particles and hidden-sector photons. The new experiments improve the existing bounds from the older BFRT experiment by a factor of two. Moreover, we use the new PVLAS constraints on a possible rotation and ellipticity of light after it has passed through a strong magnetic field to constrain pure minicharged particle models. For masses <~0.05 eV, the charge is now restricted to be less than (3-4)x10^(-7) times the electron electric charge. This is the best laboratory bound and comparable to bounds inferred from the energy spectrum of the cosmic microwave background.