Light composite Higgs from an effective action for technicolor

TL;DR

This paper develops an effective action for a composite Higgs in technicolor theories, showing that in extreme walking scenarios, the Higgs can be lighter than traditionally expected, with mass limits depending on the gauge group.

Contribution

It provides a general framework for calculating the effective action and couplings of a composite Higgs across different technicolor models, including extreme walking cases.

Findings

Composite Higgs can be as light as current experimental limits in certain technicolor models.

Upper Higgs mass limit of about 700 GeV for SU(2)_TC.

Constraints on technicolor gauge groups based on Higgs mass data.

Abstract

We compute an effective action for a composite Higgs boson formed by new fermions belonging to a general technicolor non-Abelian gauge theory, using a quite general expression for the fermionic self-energy that depends on a certain parameter (alpha), that defines the technicolor theory from the extreme walking behavior up to the one with a standard operator product expansion behavior. We discuss the values of the trilinear and quadrilinear scalar couplings. Our calculation spans all the possible physical possibilities for mass and couplings of the composite system. In the case of extreme walking technicolor theories we verify that it is possible to have a composite Higgs boson with a mass as light as the present experimental limit, contrary to the usual expectation of a heavy mass for the composite Higgs boson. In this case we obtain an upper limit for the Higgs boson mass, M_H ~ 700GeV for SU(2)_TC, and the experimental data on the Higgs boson mass constrain SU(N)_TC technicolor gauge groups to be smaller than SU(10)_TC.