The Fraternal WIMP Miracle

TL;DR

This paper explores a natural dark matter candidate in the fraternal twin Higgs model, predicting a WIMP miracle with testable direct detection signals near current experimental bounds.

Contribution

It introduces the concept of a fraternal WIMP miracle, linking dark matter relic abundance to twin weak interactions and naturalness, with specific predictions for direct detection.

Findings

Dark matter mass between 50 and 150 GeV reproduces observed abundance.

Direct detection cross section near current LUX bounds.

Dark matter interacts via Higgs portal, weakly coupled to visible sector.

Abstract

We identify and analyze thermal dark matter candidates in the fraternal twin Higgs model and its generalizations. The relic abundance of fraternal twin dark matter is set by twin weak interactions, with a scale tightly tied to the weak scale of the Standard Model by naturalness considerations. As such, the dark matter candidates benefit from a "fraternal WIMP miracle," reproducing the observed dark matter abundance for dark matter masses between 50 and 150 GeV. However, the couplings dominantly responsible for dark matter annihilation do not lead to interactions with the visible sector. The direct detection rate is instead set via fermionic Higgs portal interactions, which are likewise constrained by naturalness considerations but parametrically weaker than those leading to dark matter annihilation. The predicted direct detection cross section is close to current LUX bounds and presents an opportunity for the next generation of direct detection experiments.