New limit on the mass of 14.4-keV solar axions emitted in an M1 Transition in [sup.57]Fe nuclei

Axions of energy 14.4 keV that originated from the Ml transition in [sup.57]Fe nuclei in the Sun were sought by using the resonance-absorption reaction A + [sup.57]Fe → [sup.57]Fe * → [sup.57]Fe + γ (14.4 keV). A sectioned Si(Li) detector arranged in a low-background facility was used to record photons from this reaction. This resulted in setting a new limit on the axion couplings to nucleons, [absolute value of -l.19[g.sup.0.sub.AN] + [g.sup.3.sub.AN]] ≤ 3.0 x [10.sup.-6]. Within the hadronic-axion model, the respective constraint on the axion mass is [m.sub.A] ≤ 145 eV (at a 95% C.L.).