# Boosting Assisted Annihilation for a Cosmologically Safe MeV Scale Dark Matter

## TL;DR

This paper introduces a boosted assisted annihilation mechanism that allows for cosmologically safe MeV-scale dark matter with perturbative couplings, by enhancing the annihilation cross section through a novel process involving an assister.

## Contribution

It proposes a new assisted annihilation process that can boost the effective cross section, enabling MeV-scale dark matter consistent with cosmological constraints.

## Key findings

- Enhanced annihilation cross section via assisted annihilation.
- Feasibility of ~100 MeV dark matter with perturbative couplings.
- Compatibility with big bang nucleosynthesis and CMB constraints.

## Abstract

Assisted annihilation generates thermal sub-GeV dark matter through a novel annihilation between a pair of dark matter and standard-model-like states, called the "assister". We show that, depending on the mass hierarchy between the assister and dark matter, there can be either a suppression or a boost of the effective cross section. This augmentation enables the possibility of $\mathcal{O}(100)$ MeV scale dark matter with perturbative coupling that saturates the relic density estimates while being relatively insulated from cosmological constraints like big bang nucleosynthesis and cosmic microwave background.