Ultraheavy multiscattering dark matter: DUNE, CYGNUS, kilotonne detectors, and tidal streams

TL;DR

This paper explores multi-scatter signatures in large-volume dark matter detectors, analyzing their sensitivity to high cross-section particles and the potential to detect galactic tidal streams through velocity reconstruction.

Contribution

It provides updated reach estimates for various proposed detectors and demonstrates the possibility of identifying tidal streams via event-by-event velocity reconstruction.

Findings

Detectors can probe large scattering cross sections up to optical thickness.

Halo substructure like tidal streams can be detected if they constitute about 10% of local dark matter.

Event-by-event velocity reconstruction enables inference of dark matter velocity distribution.

Abstract

In direct searches of dark matter, multi-scatter signatures are now being sought to probe scattering cross sections that are large enough to make the detector optically thick to incident particles. We provide some significant updates to the multi-scatter program. Using considerations of energy deposition, we derive the reaches in cross section and mass of various proposed large-volume detectors: a kilotonne fiducial mass "module of opportunity" at DUNE, a kilotonne xenon detector suggested for neutrinoless double beta decay, the gaseous detector CYGNUS, and the dark matter detectors XLZD and Argo. Where the velocity vector can be reconstructed event-by-event, the Galactic dark matter velocity distribution may be inferred. We exploit this to show that halo substructure such as tidal streams can be picked up if they make up about 10% of the local dark matter density.