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

Abstract

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 ${g}_{a\ensuremath{\gamma}\ensuremath{\gamma}}<2.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}{\mathrm{GeV}}^{\ensuremath{-}1}$, independent of axion mass up to $\ensuremath{\sim}1\mathrm{keV}$.