# Primordial Extremal Black Holes as Dark Matter

## TL;DR

This paper proposes that primordial near-extremal black holes with a dark electromagnetism could be stable dark matter candidates, with observable merger signals and implications for fundamental physics.

## Contribution

It introduces a model where primordial extremal black holes serve as dark matter and predicts observable signatures from mergers, linking dark matter to the weak gravity conjecture.

## Key findings

- Primordial extremal black holes can be stable dark matter candidates.
- Merger events produce detectable high-energy neutrino and gamma-ray signals.
- The model connects dark matter properties to fundamental physics principles.

## Abstract

We show that primordial (nearly) extremal black holes with a wide range of masses from the Planck scale to around $10^9$ g could be cosmologically stable and explain dark matter, given a dark electromagnetism and a heavy dark electron. For individual black holes, Hawking radiation and Schwinger discharge processes are suppressed by near-extremality and the heaviness of the dark electron, respectively. In contrast, the merger events of binary systems provide an opportunity to directly observe Hawking radiation. Because the merger products are not extremal, they rapidly evaporate and produce transient high-energy neutrino and gamma ray signals that can be observed at telescopes like IceCube and HAWC. The relationship between the near-extremal black hole and dark electron masses could also shed light on the weak gravity conjecture.