Two Component Singlet-Triplet Scalar Dark Matter and Electroweak Vacuum Stability

TL;DR

This paper introduces a two-component dark matter model with scalar singlet and triplet, demonstrating its viability below TeV scales and showing it stabilizes the electroweak vacuum up to the Planck scale.

Contribution

It proposes a novel two-component dark matter framework with distinct $Z_2$ symmetries, enabling sub-TeV dark matter masses and vacuum stability.

Findings

Viable parameter space for sub-TeV dark matter masses.

Lighter triplet scalar as dominant dark matter component.

Electroweak vacuum remains stable up to the Planck scale.

Abstract

We propose a two component dark matter set-up by extending the Standard Model with a singlet and a hypercharge-less triplet scalars, each of them being odd under different $Z_2$ symmetries. We observe that the inter-conversion between the two dark matter components allow a viable parameter space where masses of both the dark matter candidates can be below TeV, even though their individual contribution to single component dark matter rules out any such sub-TeV dark matter. We find that a lighter mass of the neutral component of the scalar triplet, playing the role of one dark matter component, compared to the scalar one is favored. In addition, the set-up is shown to make the electroweak vacuum absolutely stable till the Planck scale, thanks to Higgs portal coupling with the scalar dark matter components.