The $Z_5$ model of two-component dark matter

TL;DR

This paper explores the phenomenology of a two-component dark matter model based on a $Z_5$ symmetry, revealing new interactions and viable parameter space below the TeV scale with detectable signals.

Contribution

It introduces the first detailed study of the $Z_5$ two-component dark matter model, highlighting novel interactions and phenomenological implications.

Findings

Dark matter masses below TeV are compatible with current data.

Interactions between dark matter components affect relic densities and detection prospects.

Both dark matter particles could produce detectable signals in future experiments.

Abstract

Scenarios for multi-component scalar dark matter based on a single $Z_N$ ($N\geq 4$) symmetry are simple and well-motivated. In this paper we investigate, for the first time, the phenomenology of the $Z_5$ model for two-component dark matter. This model, which can be seen as an extension of the well-known singlet scalar model, features two complex scalar fields--the dark matter particles--that are Standard Model singlets but have different charges under a $Z_5$ symmetry. The interactions allowed by the $Z_5$ give rise to novel processes between the dark matter particles that affect their relic densities and their detection prospects, which we study in detail. The key parameters of the model are identified and its viable regions are characterized by means of random scans. We show that, unlike the singlet scalar model, dark matter masses below the TeV are still compatible with present data. Even though the dark matter density turns out to be dominated by the lighter component, we find that current and future direct detection experiments may be sensitive to signals from both dark matter particles.