Spin-Dependent Weakly-Interacting-Massive-Particle--Nucleon Cross Section Limits from First Data of PandaX-II Experiment

Abstract

New constraints are presented on the spin-dependent WIMP-nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3$\times 10^4$ kg-days. Assuming a standard axial-vector spin-dependent WIMP interaction with ${}^{129}$Xe and ${}^{131}$Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10 GeV/c${}^2$ are set in all dark matter direct detection experiments. The minimum upper limit of $4.1\times 10^{-41}$ cm${}^2$ at 90\% confidence level is obtained for a WIMP mass of 40 GeV/c${}^2$. This represents more than a factor of two improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

5 pages, 5 figures, version accepted for publication in PRL