2017/05/31 by CAST collaboration, V. Anastassopoulos, S. Aune +64 · 1 citation
Physics and Astronomy · #hep-ex #physics.ins-det
paper · pdf · doi:10.1038/nphys4109
published as Nature Phys. 13 (2017) 584-590 · Second version after referees comments (post-print). Published version available Open Access at https://www.nature.com/articles/nphys4109
arxiv created 2017/12/20 · arxiv updated 2017/12/21
During 2003--2015, the CERN Axion Solar Telescope (CAST) has searched for a→γ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. In its final phase of solar axion searches (2013--2015), CAST has returned to evacuated magnet pipes, which is optimal for small axion masses. The absence of a significant signal above background provides a world leading limit of gaγ < 0.66 × 10-10 \rm GeV-1 (95% C.L.) on the axion-photon coupling strength for ma \lesssim 0.02 eV. Compared with the first vacuum phase (2003--2004), the sensitivity was vastly increased with low-background x-ray detectors and a new x-ray telescope. These innovations also serve as pathfinders for a possible next-generation axion helioscope.