Solar Gamma Rays Powered by Secluded Dark Matter

TL;DR

This paper explores how secluded dark matter models can produce detectable gamma rays and charged particles from the Sun and planets, offering new ways to probe dark matter with existing and future telescopes.

Contribution

It demonstrates that current water Cherenkov detectors already constrain these models and highlights the potential of high-resolution gamma-ray telescopes for future detection.

Findings

Existing water Cherenkov detectors constrain secluded dark matter models.

High angular resolution gamma-ray telescopes can improve detection prospects.

Charged particle fluxes from mediator decays may contribute to solar system cosmic rays.

Abstract

Secluded dark matter models, in which WIMPs annihilate first into metastable mediators, can present novel indirect detection signatures in the form of gamma rays and fluxes of charged particles arriving from directions correlated with the centers of large astrophysical bodies within the solar system, such as the Sun and larger planets. This naturally occurs if the mean free path of the mediator is in excess of the solar (or planetary) radius. We show that existing constraints from water Cerenkov detectors already provide a novel probe of the parameter space of these models, complementary to other sources, with significant scope for future improvement from high angular resolution gamma-ray telescopes such as Fermi-LAT. Fluxes of charged particles produced in mediator decays are also capable of contributing a significant solar system component to the spectrum of energetic electrons and positrons, a possibility which can be tested with the directional and timing information of PAMELA and Fermi.