Status of CAST and Solar Chameleon searches

CERN Axion Solar Telescope (CAST) is the most powerful axion helioscope searching for axions and axion-like particles produced in the Sun. CAST completed its search for solar axions with $^{3}$He buffer gas in the magnet bores, covering axion masses up to 1.2 eV. In the absence of excess X-rays it has set the best experimental limit on the axion-photon coupling constant over a broad range of axion masses. In 2013 CAST has improved its sensitivity to solar axions with rest mass below 0.02 eV by using Micromegas detectors and it will continue in 2014 with the implementation of a second X-ray optic and a new type detector (InGrid). In 2013 CAST has extended its sensitivity into the sub-keV energy range using a silicon detector (SDD), to search for solar chameleons, extending its searches to the dark energy sector. This search will be continued in 2014 and 2015 as well with the InGrid detector. Future axion searches can improve the current axion sensitivity by 1 to 1.5 orders of magnitude with a new generation axion telescope (IAXO)