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

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 2.7×10⁴ kg day. No solar axion or galactic axionlike dark matter particle candidate has been identified. The upper limit on the axion-electron coupling (gAe) from the solar flux is found to be about 4.35×10^-12 in the mass range from 10^-5 to 1 keV/c² with 90% confidence level, similar to the recent LUX result. We also report a new best limit from the ⁵⁷Fe deexcitation. On the other hand, the upper limit from the galactic axions is on the order of 10^-13 in the mass range from 1 to 10 keV/c² with 90% confidence level, slightly improved compared with the LUX.