# Some Implications of the Leptonic Annihilation of Dark Matter: Possible Galactic Radio Emission Signatures and the Excess Radio Flux of Extragalactic Origin

## TL;DR

This paper predicts radio signals from dark matter annihilation into leptons, suggesting certain channels could produce detectable galactic and extragalactic radio emissions within specific frequency ranges.

## Contribution

It introduces theoretical models for radio emissions from dark matter annihilating into 2- and 4-lepton states, highlighting the significance of intermediate boson channels.

## Key findings

- 4-lepton channels can produce stronger radio signatures than direct annihilation.
- Radio emissions from these channels are significant between 20 MHz and 5 GHz.
- Predicted signals could explain some observed extragalactic radio excess.

## Abstract

We give theoretical predictions for the radio emission of a dark matter candidate annihilating into 2-lepton and 4-lepton final states. We then compare our results with the known radio measurements of the sky temperature as a function of the frequency. In particular, we calculate the radio emission for some dark matter candidates annihilating into intermediate bosons that subsequently decay into a 4-lepton channel with a thermal annihilation cross-section. We show that within the range of frequencies from $20\,{\rm MHz}$ to $5\,{\rm GHz}$, this channel can produce a stronger signature than direct annihilation into leptons.