The Light Composite Higgs in Strong Extended Technicolor

TL;DR

This paper explores a model where the Higgs boson is a light composite scalar resulting from strong extended technicolor interactions, and discusses potential experimental signatures at the LHC.

Contribution

It extends previous work by incorporating technicolor effects, proposing a solution that maintains the lightness of the Higgs, and links technicolor bound states to observed diboson excesses at the LHC.

Findings

The Higgs mass can be much smaller than the extended technicolor scale through fine-tuning.

Technicolor bound states are predicted to be much heavier than the Higgs, around the TeV scale.

Possible identification of technicolor resonances with observed diboson excesses at 2 TeV.

Abstract

This paper extends an earlier one describing the Higgs boson $H$ as a light composite scalar in a strong extended technicolor model of electroweak symmetry breaking. The Higgs mass $M_H$ is made much smaller than $\Lambda_{ETC}$ by tuning the ETC coupling very close to the critical value for electroweak symmetry breaking. The technicolor interaction, neglected in the earlier paper, is considered here. Its weakness relative to extended technicolor is essential to understanding the lightness of $H$ compared to the low-lying spin-one technihadrons. Technicolor cannot be completely ignored, but implementing technigluon exchange together with strong extended technicolor appears difficult. We propose a solution that turns out to leave the results of the earlier paper essentially unchanged. An argument is then presented that masses of the spin-one technifermion bound states, $\rho_H$ and $a_H$, are much larger than $M_H$ and, plausibly, controlled by technicolor. Assuming $M_{\rho_H}$ and $M_{a_H}$ are in the TeV-energy region, we identify $\rho_H$ and $a_H$ with the diboson excesses observed near $2\,{\rm TeV}$ by ATLAS and CMS in LHC Run 1 data, and we discuss their phenomenology for Runs 2 and 3.