Pushing the frontier of WIMPy inelastic dark matter: journey to the end of the periodic table

TL;DR

This paper investigates how low-background experiments with heavy isotopes can detect inelastic dark matter, setting new bounds and forecasting future sensitivities for dark matter with large mass splittings.

Contribution

It introduces a novel approach using heavy nuclear isotopes and scintillating bolometers to probe inelastic dark matter beyond traditional methods.

Findings

New bounds on WIMPy inelastic dark matter up to 640 keV mass splitting

Demonstrated the effectiveness of heavy isotopes in dark matter detection

Forecasted future experiment sensitivities

Abstract

We explore the reach of low-background experiments made of small quantities of heavy nuclear isotopes in probing the parameter space of inelastic dark matter that is kinematically inaccessible to classic direct detection experiments. Through inelastic scattering with target nuclei, dark matter can yield a signal either via nuclear recoil or nuclear excitation. We present new results based on this approach, using data from low-energy gamma quanta searches in low-background experiments with Hf and Os metal samples, and measurements with CaWO$_4$ and PbWO$_4$ crystals as scintillating bolometers. We place novel bounds on WIMPy inelastic dark matter up to mass splittings of about 640 keV, and provide forecasts for the reach of future experiments.