Dynamical symmetry breaking from the top

Chesterman, Helen Marie (1991) Dynamical symmetry breaking from the top. University of Southampton, Doctoral Thesis.

Abstract

We study a model of dynamical symmetry breaking, known as the top mode standard model (TMSM), where the electroweak symmetry is broken by a condensate of top quarks. We study the top quark bound states of the theory and show that a tightly bound vector state does not form. A Bethe-Salpeter approach to the scalar bound state of the theory is considered. The Schwinger-Dyson (S-D) gap equation for the top-quark self energy function in the approximation of keeping only leading log QCD corrections is solved and the solution inserted into the BS amplitude for PROB*LEM → PROB*LEM scattering in the same level of approximation. A numerical search is made for the poles in the scalar and psudeo-scalar channels. Predictions for the Higgs mass in this approximation are given and compared with results from renormalization group (RG) analysis. The two sets of results are found to be in reasonable agreement. A four-family model is considered and results from both RG and BS analysis are compared. Results show good agreement between the two approaches even in the low cut-off region Λ= 1 - 10 TeV where RG predictions are least reliable. Within the framework of the TMSM we describe how experimental bounds may be placed on the scale Λ from longitudinal vector boson scattering experiments at the SSC or LHC. The main point is to show that the TMSM is testable at the SSC (LHC) providing the cutoff is sufficiently low. We illustrate our strategy by considering three production channels, namely Z^oZ^o, W^+ W^-, and Z^oW^PROB*LEM. Our tree level results indicate that the SSC (LHC) will be able to set limits on Λ of about 5TeV (2TeV).

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