# Direct detection of primordial black hole relics as dark matter

## TL;DR

This paper explores the possibility that stable, charged primordial black hole relics could make up dark matter, and assesses their detectability with current and future terrestrial experiments.

## Contribution

It introduces the idea that charged Planck-scale black hole relics could be detectable as dark matter candidates, providing a new avenue for experimental searches.

## Key findings

- Relic black holes could carry electric charge, making them detectable.
- Current experiments may already constrain or detect such relics within the next decade.
- Detection of such relics would have profound implications for cosmology and fundamental physics.

## Abstract

If dark matter is composed of primordial black holes, such black holes can span an enormous range of masses. A variety of observational constraints exist on massive black holes, and black holes with masses below $10^{15}\,\mathrm{g}$ are often assumed to have completely evaporated by the present day. But if the evaporation process halts at the Planck scale, it would leave behind a stable relic, and such objects could constitute the entirety of dark matter. Neutral Planck-scale relics are effectively invisible to both astrophysical and direct detection searches. However, we argue that such relics may typically carry electric charge, making them visible to terrestrial detectors. We evaluate constraints and detection prospects in detail, and show that if not already ruled out by monopole searches, this scenario can be largely explored within the next decade using existing or planned experimental equipment. A single detection would have enormous implications for cosmology, black hole physics, and quantum gravity.