Testing Complex Singlet Scalar Cosmology at the Large Hadron Collider

TL;DR

This paper investigates the potential for discovering a complex singlet scalar extension of the Standard Model at the LHC, focusing on its implications for electroweak phase transition, dark matter, and collider signatures.

Contribution

It provides an analysis of the LHC's reach for detecting a heavy singlet-like scalar within a model that addresses baryogenesis and dark matter.

Findings

Identifies parameter regions compatible with electroweak baryogenesis and dark matter constraints.

Analyzes the LHC's sensitivity to the $b\bar{b}+\text{MET}$ final state from scalar decays.

Constrains model parameters using current collider and precision measurements.

Abstract

The Standard Model extended with a complex singlet scalar (cxSM) can admit a strong first order electroweak phase transition (SFOEWPT) as needed for electroweak baryogenesis and provide a dark matter (DM) candidate. The presence of both a DM candidate and a singlet-like scalar that mixes with the Standard Model Higgs boson leads to the possibility of a $b\bar{b}+\text{MET}$ final state in $pp$ collisions. Focusing on this channel, we analyze the prospective reach at the Large Hadron Collider (LHC) for a heavy singlet-like scalar in regions of cxSM parameter space compatible with a SFOEWT and DM phenomenology. We identify this parameter space while implementing current constraints from electroweak precision observable and Higgs boson property measurements as well as those implied by LHC heavy resonance searches.