One light composite Higgs boson facing electroweak precision tests
Abstract
We study analytically and numerically the bounds imposed by the electroweak precision tests on a minimal composite Higgs model. The model is based on spontaneous SO(5)/SO(4) breaking, so that an approximate custodial symmetry is preserved. The Higgs arises as a pseudo-Goldstone boson at a scale below the electroweak symmetry breaking scale. We show that one can satisfy the electroweak precision constraints without much fine-tuning. This is the case if the left-handed top quark is fully composite, which gives a mass spectrum within the reach of the LHC. However a composite top quark is strongly disfavoured by flavour physics. The alternative is to have a singlet top partner at a scale much lighter than the rest of the composite fermions. In this case the top partner would be light enough to be produced significantly at the LHC.
Cite
@article{arxiv.0806.3450,
title = {One light composite Higgs boson facing electroweak precision tests},
author = {Marc Gillioz},
journal= {arXiv preprint arXiv:0806.3450},
year = {2010}
}
Comments
15 pages, 4 figures; v2: figures and discussion improved, references added; v3: minor changes, final version to appear in PRD