Axion interpretation of the PVLAS data?

Abstract

The PVLAS collaboration has recently reported the observation of a rotation of the polarization plane of light propagating through a transverse static magnetic field. Such an effect can arise from the production of a light, m A ∼ meV, pseudoscalar coupled to two photons with coupling strength gAγ ∼ 5 × 10-6 GeV-1. Here, we review these experimental findings, discuss how astrophysical and helioscope bounds on this coupling can be evaded, and emphasize some experimental proposals to test the scenario. © 2006 IOP Publishing Ltd.