Limits on Axion Couplings from the First 80 Days of Data of the PandaX-II Experiment

Abstract

We report new searches for solar axions and galactic axionlike dark matter particles, using the first low-background data from the PandaX-II experiment at China Jinping Underground Laboratory, corresponding to a total exposure of about $2.7\ifmmode\times\else\texttimes\fi{}{10}^{4}\text{ }\text{ }\mathrm{kg}\text{ }\text{day}$. No solar axion or galactic axionlike dark matter particle candidate has been identified. The upper limit on the axion-electron coupling (${g}_{Ae}$) from the solar flux is found to be about $4.35\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}$ in the mass range from ${10}^{\ensuremath{-}5}$ to $1\text{ }\text{ }\mathrm{keV}/{c}^{2}$ with 90% confidence level, similar to the recent LUX result. We also report a new best limit from the $^{57}\mathrm{Fe}$ deexcitation. On the other hand, the upper limit from the galactic axions is on the order of ${10}^{\ensuremath{-}13}$ in the mass range from 1 to $10\text{ }\text{ }\mathrm{keV}/{c}^{2}$ with 90% confidence level, slightly improved compared with the LUX.