Axion results: what is new?

Abstract

The PVLAS collaboration has obtained results that may be interpreted in terms of a light axion-like particle, while the CAST collaboration has not found any signal of such particles. Moreover, the PVLAS results are in gross contradiction with astrophysical bounds. We develop a particle physics model with two paraphotons and with a low energy scale in which these apparent inconsistencies are circumvented.

Comments: 10 pages, 4 figures. Based on two talks given at the International Workshop "The dark side of the Universe", Madrid, June 2006: "Evading astrophysical bounds on axion-like particles in paraphoton models" by J. Redondo and "Axion results: what is new?" by E. Masso. To be published in the Proceedings