Uncovering the High Scale Higgs Singlet Model

TL;DR

This paper re-evaluates constraints on the high-scale Higgs singlet extension of the Standard Model using electroweak precision data, LHC results, and effective field theory techniques, providing new analytic expressions and comprehensive parameter space analysis.

Contribution

It offers a detailed re-analysis of the high-scale Higgs singlet model, including analytic expressions, unitarity and stability constraints, and a global fit incorporating both tree-level and 1-loop effects.

Findings

Constraints on the scalar mass and mixing from electroweak data.

Mapping onto SMEFT provides bounds on high-scale parameters.

Inclusion of 1-loop effects refines the allowed parameter space.

Abstract

The scalar singlet model extends the Standard Model with the addition of a new gauge singlet scalar. We re-examine 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 (SMEFT) 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 1-loop.