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 g_{Aγ} ~ 5x10^{-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.

Figures (1)

• Figure 1: Exclusion region in mass $m_A$ vs. axion-photon coupling $g_{A\gamma}$ for various current and future experiments. The laser experiments Cameron:mrZavattini:2005tmRingwald:2001cpRingwald:2003ns aim at axion production and detection in the laboratory. The galactic dark matter experiments Eidelman:2004wy exploit microwave cavities to detect axions under the assumption that axions are the dominant constituents of our galactic halo, and the solar experiments search for axions from the sun Andriamonje:2004hi. The constraint from horizontal branch (HB) stars Eidelman:2004wyRaffelt:1999tx arises from a consideration of stellar energy losses through axion production.