Technicolor with a 125 GeV Higgs Boson

TL;DR

This paper examines the constraints on bosonic technicolor models with a 125 GeV Higgs, showing that vacuum stability severely limits their parameter space due to the interplay of Higgs quartic and top Yukawa couplings.

Contribution

It identifies the narrow parameter space where bosonic technicolor models remain vacuum stable or metastable with a long lifetime at the observed Higgs mass.

Findings

Vacuum stability constrains bosonic technicolor models at 125 GeV.

The Higgs quartic coupling remains positive only in a narrow parameter region.

Allowing metastability slightly enlarges the viable parameter space.

Abstract

Bosonic technicolor models accommodate fermion masses via a Higgs doublet that acquires a vacuum expectation value when technifermions condense. We point out that these models are severely constrained by vacuum stability if the Higgs boson mass is near 125 GeV, the value suggested by LHC data. The Higgs quartic coupling in bosonic technicolor is typically smaller at the weak scale than in the Standard Model, while the top quark Yukawa coupling is larger. We find that the running quartic coupling remains positive below a reasonably defined cut off only in a narrow region of the model's parameter space. This region is only slightly enlarged if one allows a metastable vacuum with a lifetime longer than the age of the universe.