S and T Parameters in the Fermion Condensate Model

Abstract

We calculate the oblique electroweak corrections and confront them with the experiments in a composite Higgs version of the standard model. A vector-like weak doublet and a singlet fermion are added to the standard model without elementary Higgs. Due to quartic coupling there is a mixing between the components of the new fields triggering electroweak symmetry breaking. The Peskin-Takeuchi S and T electroweak parameters are presented. The new sector of vector-like fermions is slightly constrained, T gives an upper bound on the mixing angle of the new fermions, which is already constrained by self-consistent gap-equations. S gives no constraints on the masses. This extension can give a positive contribution to T, allowing for a heavy Higgs boson in electroweak precision tests of the Standard Model.

Comments: 14 pages, 5 figures