Production and signatures of multi-flavour dark matter scenarios with t-channel mediators

TL;DR

This paper explores a multi-flavor dark matter model with two Majorana fermion generations, analyzing their production, detection prospects, and the impact of their interactions on dark matter abundance and signals.

Contribution

It introduces a multi-flavor dark matter framework with t-channel mediators, highlighting new production regimes and enhanced detection signals compared to single-flavor models.

Findings

Heavier dark matter generation can dominate relic abundance in certain parameter regions.

Dark matter coupling strengths can be significantly larger than in single-flavor scenarios.

Detection signals may be substantially boosted due to multi-flavor interactions.

Abstract

We investigate the phenomenology of a dark matter scenario containing two generations of the dark matter particle, differing only by their mass and their couplings to the other particles, akin to the quark and lepton sectors of the Standard Model. For concreteness, we consider the case where the two dark matter generations are Majorana fermions that couple to a right-handed lepton and a scalar mediator through Yukawa couplings. We identify different production regimes in the multi-flavor dark matter scenario and we argue that in some parts of the parameter space the heavier generation can play a pivotal role in generating the correct dark matter abundance. In these regions, the strength of the dark matter coupling to the Standard Model can be much larger than in the single-flavored dark matter scenario. Correspondingly the indirect and direct detection signals can be significantly boosted. We also comment on the signatures of the model from the decay of the heavier dark matter generation into the lighter.