A Natural Supersymmetric Model with MeV Dark Matter

TL;DR

This paper presents a simple, natural supersymmetric model where the lightest supersymmetric particle has an MeV-scale mass, providing a viable explanation for the Galactic 511 keV photon flux through dark matter annihilation.

Contribution

It introduces a supersymmetric model with naturally MeV-scale dark matter and mediator particles, addressing previous challenges in constructing such models.

Findings

The model naturally produces MeV-scale dark matter and mediator masses.

Small effective couplings lead to radiative corrections generating the required masses.

The model offers a viable particle physics explanation for the 511 keV photon flux.

Abstract

It has previously been proposed that annihilating dark matter particles with MeV-scale masses could be responsible for the flux of 511 keV photons observed from the region of the Galactic Bulge. The conventional wisdom, however, is that it is very challenging to construct a viable particle physics model containing MeV dark matter. In this letter, we challenge this conclusion by describing a simple and natural supersymmetric model in which the lightest supersymmetric particle naturally has a MeV-scale mass and the other phenomenological properties required to generate the 511 keV emission. In particular, the small ($\sim$ $10^{-5}$) effective couplings between dark matter and the Standard Model fermions required in this scenario naturally lead to radiative corrections that generate MeV-scale masses for both the dark matter candidate and the mediator particle.