Search for bosonic superweakly interacting massive dark matter particles with the XMASS-I detector

TL;DR

This study conducted a direct search for bosonic super-WIMPs as warm dark matter candidates using the XMASS-I detector, setting new constraints on their properties with no detection observed.

Contribution

First direct detection experiment targeting vector super-WIMPs in the 40-120 keV mass range, establishing the most stringent limits on their coupling to electrons.

Findings

No significant excess observed above background.

Excluded vector super-WIMPs as all dark matter candidates.

Set new upper limits on pseudoscalar super-WIMP coupling.

Abstract

Bosonic superweakly interacting massive particles (super-WIMPs) are a candidate for warm dark matter. With the absorption of such a boson by a xenon atom these dark matter candidates would deposit an energy equivalent to their rest mass in the detector. This is the first direct detection experiment exploring the vector super-WIMPs in the mass range between 40 and 120 keV. Using 165.9 days of data no significant excess above background was observed in the fiducial mass of 41 kg. The present limit for the vector super-WIMPs excludes the possibility that such particles constitute all of dark matter. The absence of a signal also provides the most stringent direct constraint on the coupling constant of pseudoscalar super-WIMPs to electrons. The unprecedented sensitivity was achieved exploiting the low background at a level $10^{-4}$ kg$^{-1}$keV$_{ee}^{-1}$day$^{-1}$ in the detector.