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

TL;DR

This paper proposes using high-Z material emulsion detectors in underground experiments to detect boosted dark matter from astrophysical sources through nuclear scattering and decay products, offering sensitivity in the sub-GeV mass range.

Contribution

It introduces a novel detection method employing high-Z materials and emulsion detectors to identify boosted dark matter via nuclear scattering and decay signatures.

Findings

Potential to detect boosted dark matter in the sub-GeV mass range

Enhanced sensitivity using high-Z materials like lead

Ability to distinguish signals from backgrounds such as solar neutrinos

Abstract

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. Backgrounds such as the high energy solar neutrinos can be controlled by the reconstructed track topology. The proposed detector has the potential to find a boosted DM in the sub-GeV mass region, and in certain parameter space, an observation can be made while there is no sensitivity in other large-volume detectors such as Super-K.