Search for Solar Axions by the CERN Axion Solar Telescope with ~3He Buffer Gas: Closing the Hot Dark Matter Gap

摘要

The CERN Axion Solar Telescope has finished its search for solar axions with ~3He buffer gas, covering the search range 0.64 eV (＜～) m_a (＜～) 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_(aγ) (＜～) 3.3 × 10~(-10) GeV~(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_(aγ), for example by the currently discussed next generation helioscope International AXion Observatory.