Search for 8.4-Kev Solar Axions Emitted in the M 1 Transition in 169 Tm Nuclei

Axions with an energy of 8.4 keV emitted in the М1 transition in 169Tm nuclei in the Sun are sought in the A + ^169 1ptTm → 169Tm* → ^169Tm + (γ ,e) (8.4 keV) reaction of resonant absorption by 169Tm nuclei on the Earth using a Tm_3Al_5O_12 thulium garnet crystal as a bolometric detector. The flux of monochromatic 8.4‑keV axions has been calculated. New constraints on the axion–nucleon coupling constants have been obtained and, as a result, new upper bounds on the axion mass m_A^KSVZ⩽141 eV and m_A^DFSZ⩽244 eV have been obtained at 90