Quebra Espontânea da Simetria Quiral em Modelos de Yukawa-Higgs.

Abstract

We study some problems concerning the renormalization and properties of scattering amplitudes in Yukawa-Higgs models with either one real scalar field or a complex scalar field, and with either discrete or continuous quiral symmetries. Our main goal is to investigate the effects of breaking the continuous quiral symmetry, and the specific conditions for the renormalization of the fields and the coupling constants, both in the high-energy symmetric phase and in the low-energy Higgs phase. Among the results found, we may call attention to the non-renormalization of the Yukawa coupling g in the symmetric phase. In the Higgs phase, however, g gets renormalized at one-loop. This is due to the fact that the set of fields relevant for the description of the Higgs phase has very different properties in comparison with the fields relevant for the description of the symmetric phase. Also, the realization of the spontaneous symmetry breaking includes new interaction terms. Another interesting result is the significant difference found for the behavior of scattering amplitudes and decay rates in each phase, not only for fermions but also for the scalar fields.