Search for boosted dark matter with high-Z material in underground experiments

Understand

We propose to search for a boosted dark matter (DM) particle from astrophysical sources using an emulsion detector in deep underground facilities.

• We further propose using high-$Z$ material such as the lead for a larger DM-nucleus coherent scattering cross section above a threshold.
• The boosted DM will scatter into an excited DM.
• While the nuclear recoil energy is not detected, the decay products from the excited DM can be recorded by the proposed detector.