Radiative corrections to the Higgs boson couplings in the model with an additional real singlet scalar field

TL;DR

This paper calculates one-loop level corrections to Higgs couplings in a model with an extra singlet scalar, exploring deviations from the Standard Model and potential distinguishability at future colliders.

Contribution

It provides the first detailed one-loop renormalized Higgs couplings in a singlet scalar extension, including theoretical constraints and comparison with two Higgs doublet models.

Findings

Couplings can significantly deviate from SM predictions due to mixing and loop effects.

The model can be distinguished from two Higgs doublet models via precision Higgs coupling measurements.

Theoretical constraints restrict the parameter space where deviations are observable.

Abstract

We calculate renormalized Higgs boson couplings with gauge bosons and fermions at the one-loop level in the model with an additional isospin singlet real scalar field. These coupling constants can deviate from the predictions in the standard model due to tree-level mixing effects and one-loop contributions of the extra neutral scalar boson. We investigate how they can be significant under the theoretical constraints from perturbative unitarity and vacuum stability and also the condition of avoiding the wrong vacuum. Furthermore, comparing with the predictions in the Type I two Higgs doublet model, we numerically demonstrate how the singlet extension model can be distinguished and identified by using precision measurements of the Higgs boson couplings at future collider experiments.