Uncovering the high-scale Higgs singlet model

Sally Dawson,Pier Paolo Giardino,Samuel Homiller

doi:10.1103/physrevd.103.075016

Abstract

The scalar singlet model extends the Standard Model with the addition of a new gauge singlet scalar. We reexamine the limits on the new scalar from oblique parameter fits and from a global fit to precision electroweak observables and present analytic expressions for our results. For the case when the new scalar is much heavier than the weak scale, we map the model onto the dimension-six Standard Model effective field theory and review the allowed parameter space from unitarity considerations and from the requirement that the electroweak minimum be stable. A global fit to precision electroweak data, along with LHC observables, is used to constrain the parameters of the high scale singlet model, and we determine the numerical effects of performing the matching at both tree level and one loop.

Highlights

The Higgs singlet model [1,2,3,4,5,6,7] has been extensively studied as a simple extension of the Standard Model (SM) containing only one new particle
When the mass of the new scalar becomes much larger than the weak scale, the theory can be mapped onto an effective field theory
The aim of this work is to examine to what extent the extraction of Standard Model effective field theory (SMEFT) coefficients from global fits at the weak scale gives information on the parameters of the UV complete singlet model [28,32,33,34,37,38,39]

Summary

INTRODUCTION

The Higgs singlet model [1,2,3,4,5,6,7] has been extensively studied as a simple extension of the Standard Model (SM) containing only one new particle. In the full UV complete singlet model, restrictions on the parameters can be found from fits to precision electroweak observables as well as LHC data. These limits can be compared with limits found in the context of a low energy effective field theory. The SMEFT matching with the singlet model at both tree and loop level is studied in Sec. V, and a global fit to electroweak precision observables, Higgs, and diboson data is presented.

BASICS

RESTRICTIONS ON MODEL PARAMETERS

Vacuum structure of the potential

Unitarity

One-loop matching

CONCLUSIONS