Z_5 two-component dark matter in the Type-II seesaw mechanism

TL;DR

This paper explores a Z5 two-component dark matter model within the Type-II seesaw framework, addressing relic density, detection constraints, and explaining cosmic ray excesses through dark matter annihilations involving triplets.

Contribution

It introduces a novel Z5 two-component dark matter model with triplet interactions, explaining cosmic ray excesses and analyzing parameter space under relic and detection constraints.

Findings

Both light and heavy dark matter components can fit the observed excesses.

The model's parameter space is flexible and consistent with relic density and detection constraints.

Electron-positron flux excess can be explained with dark matter masses above triplet masses.

Abstract

We consider the Z5 two-component dark matter model within the framework of the Type-II seesaw mechanism. Due to the new annihilation processes related to triplets, the light component cannot necessarily be dominant in the dark matter relic density, which is different from the Z5 two-component dark matter model in the SM. The model is considered to explain the excess of electron-positron flux measured by the AMS-02 Collaborations in this work, which is encouraged by the decay of the triplets arising from dark matter annihilations in the Galactic halo. We discuss the cases of the light and heavy components determining dark matter density within a viable parameter space satisfying relic density and direct detection constraints, and by fitting the antiproton spectrum observed in the PAMELA and AMS experiments, we find that the parameter space is flexible and the electron-positron flux excess can be obtained in both cases with the mass of two dark matter particles being larger than that of the triplets'.