New experiment on search for the resonance absorption of solar axion emitted in the M1 transition of 83Kr nuclei

Abstract

Axions with an energy of 9.4 keV emitted in the M1 transition of 83Kr nuclei in the Sun have been sought in the resonance absorption reaction A + 83Kr → 83Kr* → 83Kr + γ, e (9.4 keV). A proportional gas chamber filled with krypton and placed in a low-background setup at the underground laboratory of the Baksan neutrino observatory was used to detect γ-ray photons and electrons appearing after the decay of a nuclear level. As a result, a new constraint has been determined on the isoscalar and isovector coupling constants of the axion with nucleons: |gAN3– gAN0| ≤ 1.29 × 10–6. This constraint results in the following new bound on the mass of the axion in the hadronic axion model: mA ≤ 100 eV (95% C.L.).