Complex Singlet Extension of the Standard Model

TL;DR

This paper explores a simple extension of the Standard Model by adding a complex singlet, which can provide dark matter candidates and support electroweak baryogenesis, with implications for Higgs discovery at the LHC.

Contribution

It introduces the complex singlet extension of the SM, analyzing its potential to explain dark matter and baryogenesis, and discusses collider phenomenology.

Findings

The model can contain one or two viable dark matter candidates.

It supports a strong first order electroweak phase transition.

Implications for Higgs discovery at the LHC are discussed.

Abstract

We analyze a simple extension of the Standard Model (SM) obtained by adding a complex singlet to the scalar sector (cxSM). We show that the cxSM can contain one or two viable cold dark matter candidates and analyze the conditions on the parameters of the scalar potential that yield the observed relic density. When the cxSM potential contains a global U(1) symmetry that is both softly and spontaneously broken, it contains both a viable dark matter candidate and the ingredients necessary for a strong first order electroweak phase transition as needed for electroweak baryogenesis. We also study the implications of the model for discovery of a Higgs boson at the Large Hadron Collider.