Search for resonant absorption of solar axions emitted in M1-transitions in ⁸³Kr nuclei: Second stage of the experiment

Axions with energies of 9.4 keV putatively produced in the Sun via an M1-transition in the ⁸³Kr nucleus are searched for using the reaction of resonant absorption: A +⁸³Kr →⁸³Kr* →⁸³Kr + γ, e (9.4 keV). The γ-quanta and electrons are detected with a proportional counter filled with krypton and placed in a low-background setup. A new upper limit on the axion–nucleon coupling constant is imposed: |g³_AN g⁰_AN|≤1.02 10⁶. For the hadronic axion, this implies a new upper limit on the axion mass: m _A ≤ 79eV at the 95% confidence level.