Constraints on axion couplings from the CDEX-1 experiment at the China Jinping Underground Laboratory

Abstract

We report the results of searches for solar axions and galactic dark matter axions or axionlike particles with the CDEX-1 experiment at the China Jinping Underground Laboratory, using 335.6 kg days of data from a $p$-type point-contact germanium detector. The data are compatible with the background model, and no excess signals are observed. Limits of solar axions on the model-independent coupling ${g}_{Ae}<2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$ from Compton, bremsstrahlung, atomic-recombination, and deexcitation channels and ${g}_{AN}^{\text{eff}}\ifmmode\times\else\texttimes\fi{}{g}_{Ae}<6.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}17}$ from a $^{57}\mathrm{Fe}$ M1 transition at 90% confidence level are derived. Within the framework of the Dine-Fischler-Srednicki-Zhitnitskiy and Kim-Shifman-Vainshtein-Zakharov models, our results exclude the axion mass heavier than 0.9 and $177\text{ }\text{ }\mathrm{eV}/{\mathrm{c}}^{2}$, respectively. The derived constraints for dark matter axions below 1 keV improve over the previous results.