The latest results from CAST and the IAXO project

The CAST experiment has been the most sensitive helioscope so far. It has extended its sensitivity to the upper bounds of axion masses allowed by cosmology, entering well into the QCD-axion band. The preliminary analysis of the data taken with sensitivity to axion masses of the range 0.64 eV to 1.17 eV show no excess of signal above background and the coupling constant is restricted to g a g < 3 : 3 10 10 GeV 1 . While CAST continues with the aim to improve its results in the vacuum phase, IAXO is the new project proposed to build a dedicated magnet for axion searches that will supersede CAST’s sensitivity by one order of magnitude in g a g .