A direct dark matter search in XMASS-I

Abstract

A search for dark matter using an underground single-phase liquid xenon detector was conducted at the Kamioka Observatory in Japan, particularly for Weakly Interacting Massive Particles (WIMPs). We have used 705.9 live days of data in a fiducial volume containing 97 kg of liquid xenon at the center of the detector. The event rate in the fiducial volume after the data reduction was (4.2±0.2)×10 −3 day −1 kg −1 keV −1 ee at 5keV ee , with a signal efficiency of 20% . All the remaining events are consistent with our background evaluation, mostly of the "mis-reconstructed events" originated from 210 Pb in the copper plates lining the detector's inner surface. The obtained upper limit on a spin-independent WIMP-nucleon cross section was 2.2×10 −44 cm 2 for a WIMP mass of 60GeV/c 2 at the 90% confidence level, which was the most stringent limit among results from single-phase liquid xenon detectors. ©2018 The Author.