The Inert Doublet Model: an Archetype for Dark Matter

TL;DR

The paper analyzes the Inert Doublet Model (IDM), a minimal two-Higgs-doublet extension with a preserved Z2 symmetry, focusing on H0 as a dark matter candidate. Using thermal freeze-out and micrOMEGAs, it identifies relic-density-allowed regions in low- and high-mass regimes, with distinct annihilation channels and potential coannihilation. It then evaluates indirect detection prospects via gamma rays in the Galactic halo and direct detection via Higgs-mediated scattering, highlighting GLAST sensitivity and current CDMS constraints. The results show IDM can yield the observed DM abundance in specific parameter regions and offer potentially stronger gamma-ray signals than MSSM SUSY models, while direct detection remains most promising at low masses. The study emphasizes the IDM as a simple, yet phenomenologically rich, archetype of WIMP dark matter with observable connections to Higgs physics and collider experiments.

Abstract

The Inert Doublet Model (IDM), a two Higgs extension of the Standard Model with an unbroken $Z_2$ symmetry, is a simple and yet rich model of dark matter. We present a systematic analysis of the dark matter abundance and investigate the potentialities for direct and gamma indirect detection. We show that the model should be within the range of future experiments, like GLAST and ZEPLIN. The lightest stable scalar in the IDM is a perfect example, or archetype of a weakly interacting massive particle.

Figures (7)

• Figure 1: Annihilation channels into gauge bosons final state with corresponding couplings.
• Figure 2: Annihilation channels into Higgs final state.
• Figure 3: (Co)Annihilation channels into fermion anti-fermion final state.
• Figure 4: Leading channels contributing to $\sigma_{H_0-p}$ (direct detection).
• Figure 5: From top to bottom: Relic density, gamma indirect detection and direct detection contours in the $(M_{H_0},\mu_2)$ plane. Left: $m_h=120$ GeV. Right: $m_h=200$ GeV.