# Inception of Self-Interacting Dark Matter with Dark Charge Conjugation Symmetry

## TL;DR

This paper proposes a new model for self-interacting dark matter based on a spontaneously broken Abelian gauge symmetry with dark charge conjugation, allowing stable dark particles and avoiding cosmological constraints.

## Contribution

It introduces a minimal Abelian gauge model with dark charge conjugation symmetry that naturally stabilizes dark matter particles and mediators, addressing previous decay-related constraints.

## Key findings

- Stable dark matter particles and mediators are possible in this model.
- The light mediator remains stable and does not decay into standard-model particles.
- The model circumvents cosmological constraints on decaying mediators.

## Abstract

A new understanding of the stability of self-interacting dark matter is pointed out, based on the simplest spontaneously broken Abelian $U(1)$ gauge model with one complex scalar and one Dirac fermion. The key is the imposition of dark charge conjugation symmetry. It allows the possible existence of two stable particles: the Dirac fermion and the vector gauge boson which acts as a light mediator for the former's self-interaction. Since this light mediator does not decay, it avoids the strong cosmological constraints recently obtained for all such models where the light mediator decays into standard-model particles.