Light-shining-through-walls with lasers

TL;DR

Light-shining-through-walls experiments using lasers are a promising laboratory method to search for weakly interacting slim particles, with recent setups aiming to improve sensitivity and explore parameter regions suggested by astrophysical hints.

Contribution

The paper reviews current laser-based light-shining-through-walls experiments and highlights upcoming efforts to enhance sensitivity to axion-like particles.

Findings

ALPS I set the most stringent laboratory limits.

ALPS II aims to probe axion-like particle couplings down to |g_{aγ}| ≈ 2×10^{-11} GeV^{-1}.

Experiments are approaching parameter regions suggested by astrophysical observations.

Abstract

Light-shining-through-walls experiments are the search experiments for weakly interacting slim particles (WISPs) with the smallest model dependence. They have the advantage that not only the detection, but also the production of the WISPs takes place in the laboratory and can thus be controlled. Using lasers is the preferred option for most of the mass region and has led to the world's most stringent laboratory limits (ALPS I) there. At CERN, OSQAR promises to surpass these and at DESY ALPS II is currently set up, which is planning to probe the axion-like particle to photon coupling down to $|g_{a\gamma}|\gtrsim 2\cdot10^{-11}$ GeV$^{-1}$, which is in a region favored by many astrophysical hints.