Reducing the quadratic divergence in the Higgs boson mass squared without top partners

Sonia El Hedri,Ann E Nelson,Devin G E Walker

doi:10.1103/physrevd.98.035029

Sonia El Hedri, Ann E Nelson + Show 1 more

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https://doi.org/10.1103/physrevd.98.035029

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Abstract

We examine a model with multiple scalar fields to see whether it is possible to reduce the fine- tuning of the SM Higgs mass without introducing low scale top partners. Our approach may be regarded as a generalization of the condition proposed by Veltman, who attempted to predict the Higgs mass using the criterion that the various low energy contributions to the quadratic divergence of the Higgs mass cancel. Although the Veltman condition predicts the wrong Higgs mass in the Standard Model, it can still be adapted to extended Higgs sectors. Furthermore, theories with additional Higgs bosons can lead to suppressed Yukawa couplings of the top quark to the 125 GeV Higgs, making the associated one-loop divergence smaller. Here, we review possible extensions of the Standard Model where the Veltman condition could be realized, and study in detail one minimal model with two extra scalar fields. For this model and for a cutoff of 5 TeV, we show that the overall fine-tuning can be considerably lowered without introducing low-scale Landau poles, albeit the Higgs sector will be strongly coupled at the cutoff. Models where the top Yukawa coupling is reduced, in particular, will be within the reach of the upcoming LHC searches.

Highlights

The discovery of the Higgs boson at the Large Hadron Collider (LHC) [1,2] is a triumph for particle physics, as it was one of the last missing pieces needed to understand the origin of the masses of the Standard Model (SM) particles
In order to account for the possible mild suppressions of the production rates of these particles in our model, we focus on parameter points where h0, A0, and HÆ all have masses larger than 250 GeV, which correspond to the lowest masses explored by the 13 TeV LHC Higgs searches
We have considered the cutoff sensitivity of an extension of the minimal standard model with additional particles which only carry electroweak charges, and we argue that they should be scalars

Summary

Introduction

The discovery of the Higgs boson at the Large Hadron Collider (LHC) [1,2] is a triumph for particle physics, as it was one of the last missing pieces needed to understand the origin of the masses of the Standard Model (SM) particles. The mass of the Higgs boson, 125 GeV, is sensitive to physics at much higher scales. At one-loop, the SM Higgs mass squared receives sizable corrections that depend quadratically on the cutoff energy scale, Λ, as follows: m2h 1⁄4.

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