Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer

Results are reported of an experimental search for the unique, rapidly varying temporal pattern of solar axions coherently converting into photons via the Primakoff effect in a single crystal germanium detector when axions are incident at a Bragg angle with a crystalline plane. The analysis of 1.94 kg yr of data from the 1 kg DEMOS detector in Sierra Grande, Argentina, yields a new laboratory bound by an axion-photon coupling of $g_{a\gamma \gamma }<2.7\mathrm{}\times {10}^{-9\mathrm{}}{\mathrm{GeV}}^{-1\mathrm{}}$, independent of axion mass up to $\sim 1\mathrm{keV}$.