Search for dark matter from the first data of the PandaX-II experiment

Abstract: Results of WIMP dark matter search from the first data of the PandaX-II experiment are presented. PandaX-II experiment uses a 500 kg scale dual phase liquid xenon time projection chamber, operating at the China JinPing Underground Laboratory. The first data correspond to a total exposure of $3.1\times10^{4}$ kg-day. The observed data after selections are found to be consistent with background expection, and upper limits of the spin-independent WIMP-nucleon cross sections are derived for a range of WIMP mass between 5 GeV/c$^2$ and 1000 GeV/$c^{2}$. The lowest cross section limit obtained is 2.5$\times$10$^{-46}$ cm$^2$ at a WIMP mass of 40 GeV/c$^2$.