Inert Doublet Dark Matter with Strong Electroweak Phase Transition

TL;DR

This paper investigates the inert doublet dark matter model's ability to produce a strong electroweak phase transition suitable for baryogenesis, considering experimental constraints and predicting specific dark matter mass ranges and collider signatures.

Contribution

It provides a detailed analysis of the electroweak phase transition strength in the inert doublet model with accurate one-loop finite temperature potential, identifying viable parameter space.

Findings

Significant parameter space allows strong EWPT compatible with dark matter constraints.

Dark matter mass predicted in the 60-67 GeV range.

Potential LHC signatures include altered Higgs decay channels.

Abstract

We reconsider the strength of the electroweak phase transition (EWPT) in the inert doublet dark matter model, using a quantitatively accurate form for the one-loop finite temperature effective potential, taking into account relevant particle physics and dark matter constraints, focusing on a standard model Higgs mass near 126 GeV, and doing a full scan of the space of otherwise unconstrained couplings. We find that there is a significant (although fine-tuned) space of parameters for achieving an EWPT sufficiently strong for baryogenesis while satisfying the Xenon100 constraints from direct detection and not exceeding the correct thermal relic density. We predict that the dark matter mass should be in the range 60-67 GeV, and we discuss possible LHC signatures of the charged and CP-odd Higgs bosons, including a 10% decrease of the h -> 2 photon branching ratio.