Zeplin I: First Limits On Nuclear Recoil Rate

First preliminary results from the Zeplin I WIMP dark matter detector are presented. They are based on the measurements of scintillation pulse shapes in liquid xenon target with 3.2 kg fiducial mass. The detector was located in the Boulby Underground Laboratory (North Yorkshire, UK) at a depth of 2800 m w. e. The data collected dirung 91.5 days did not reveal the presence of second population of events faster than expected from gamma-induced electron recoils. Based on these results new limits were set on the spin-independent WIMP-nucleon and spin-dependent WIMP-neutron cross-sections.