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

Abstract

Various 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 $1.0\mathrm{ke}{\mathrm{V}}_{\mathrm{ee}}$. In the latter half of data taking a lower analysis threshold of $0.5\mathrm{ke}{\mathrm{V}}_{\mathrm{ee}}$ 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 $1.4\times 10^{-44}\mathrm{c}{\mathrm{m}}^2$ for a $60GeV/{\mathrm{c}}^2$ 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 $8GeV/{\mathrm{c}}^2$ WIMP this analysis yielded a 90\% CL cross section limit of $2.3\times 10^{-42}\mathrm{c}{\mathrm{m}}^2$. At a WIMP mass of $0.5GeV/{\mathrm{c}}^2$ the Migdal effect and Bremsstrahlung signatures were evaluated and lead to 90\% CL cross section limits of $1.4\times 10^{-35}\mathrm{c}{\mathrm{m}}^2$ and $1.1\times 10^{-33}\mathrm{c}{\mathrm{m}}^2$ respectively.