Dark energy, scalar singlet dark matter and the Higgs portal

TL;DR

This paper explores an extended scalar singlet dark matter model with higher-dimensional interactions, showing how it can account for cosmic acceleration via a false vacuum while maintaining stability and distinct running behaviors.

Contribution

It introduces dimension-six and dimension-eight interaction terms in the scalar singlet dark matter model, analyzing their effects on vacuum stability and cosmic acceleration.

Findings

Dimension-six term enables false vacuum for cosmic acceleration.

Dimension-eight term allows accelerated expansion with a stable potential.

False vacuum decay is highly suppressed in the extended model.

Abstract

One of the simplest extensions of the Standard Model (SM) comprises the inclusion of a massive real scalar field, neutral under the SM gauge groups, to be a dark matter candidate. The addition of a dimension-six term into the potential of the scalar dark matter enables the appearance of a false vacuum that describes the cosmic acceleration. We show that the running of the singlet self-interaction and the Higgs portal coupling differs from the standard scalar singlet dark matter model. If we maintain a positive quartic coupling, it is also possible to describe the accelerated expansion of the Universe through a false vacuum with the addition of a dimension-eight interaction term. In this case, where the potential remains bounded from below at low energies, the false vacuum decay is highly suppressed.