Search for Solar Axions Produced by Primakoff Conversion Using Resonant Absorption by ${}^{169}$Tm Nuclei

Abstract

The search for resonant absorption of the Primakoff solar axions by ${}^{169}$Tm nuclei have been performed. Such an absorption should lead to the excitation of low-lying nuclear energy level: $A{+}^{169}$Tm ${\to }^{169}$Tm${}^{\ast }$ ${\to }^{169}$Tm$+\gamma$ (8.41 keV). The Si(Li) detector and ${}^{169}$Tm target placed inside the low-background setup were used for that purpose. As a result, a new restriction on the axion-photon coupling and axion mass was obtained: $g_{A\gamma }({GeV}^{-1})\cdot m_A(eV)\le 1.36\cdot 10^{-5}$ (90% c.l.). In model of hadronic axion this restriction corresponds to the upper limit on axion mass - $m_A\le$ 191 eV for 90% c.l.

Comments: 6 pages, 5 figures, submitted to Physics Letters B