  Axions were originally proposed to explain the strong-CP problem in QCD.
Through the axion-photon coupling, the Sun could be a major source of axions,
which could be measured in solid state detection experiments with enhancements
due to coherent Primakoff-Bragg scattering. The Majorana Demonstrator
experiment has searched for solar axions with a set of $^{76}$Ge-enriched high
purity germanium detectors using a 33 kg-yr exposure collected between Jan.
2017 and Nov. 2019. A temporal-energy analysis gives a new limit on the
axion-photon coupling as $g_{a\gamma}<1.45\times 10^{-9}$ GeV$^{-1}$ (95% C.I.)
for axions with mass up to 100 eV/$c^2$. This improves laboratory-based limits
between about 1 eV/$c^2$ and 100 eV/$c^2$.
