Limits on spin-dependent WIMP-nucleon cross-sections from the first ZEPLIN-II data ZEPLIN-II Collaboration

The first underground data run of the ZEPLIN-II experiment has set a limit on the nuclear recoilrate in the two-phase xenondetector for direct dark matter searches. In this Letter the results from this run are converted into the limits on spin-dependent WIMP-proton and WIMP- neutron cross-sections. The minimum of the curve for WIMP- neutron cross-sectioncorresponds to 7 × 10 −2 pb at a WIMPmass of around 65 GeV.