Direct dark matter searches with the full data set of XMASS-I

Abstract

Various weakly interacting massive particle (WIMP) dark matter searches using the full data set of XMASS-I, a single-phase liquid xenon detector, are reported in this paper. Stable XMASS-I data taking accumulated a total live time of 1590.9 days between November 20, 2013 and February 1, 2019 with an analysis threshold of 1.0 keVee. In the latter half of data taking a lower analysis threshold of 0.5 keVee was also available through a new low threshold trigger. Searching for a WIMP signal in the detector's 97 kg fiducial volume yielded a limit on the WIMP-nucleon scattering cross section of 1.4 x 10-44 cm2 for a 60 GeV/c2 WIMP at the 90% confidence level. We also searched for WIMP induced annual modulation signatures in the detector's whole target volume, containing 832 kg of liquid xenon. For nuclear recoils of a 8 GeV/c2 WIMP this analysis yielded a 90% confidence level (CL) cross section limit of 2.3 x 10-42 cm2. Annual modulation signatures from the Migdal effect and bremsstrahlung at a WIMP mass of 0.5 GeV/c2 are evaluated and lead to 90% CL cross section limits of 1.4 x 10-35 cm2 and 1.1 x 10-33 cm2, respectively.