Conformal Symmetry and the Standard Model

Abstract

We re-examine the question of radiative symmetry breaking in the standard model in the presence of right-chiral neutrinos and a minimally enlarged scalar sector. We demonstrate that, with these extra ingredients, the hypothesis of classically unbroken conformal symmetry, besides naturally introducing and stabilizing a hierarchy, is compatible with all available data; in particular, there exists a set of parameters for which the model may remain viable even up to the Planck scale. The decay modes of the extra scalar field provide a unique signature of this model which can be tested at LHC.

Figures (2)

• Figure 1: Production of $Z_0$ pairs in a) Higgs and b) new scalar channels (resonant production is possible if $m_H>2m_Z$ or $m_\varphi>2m_Z$)
• Figure 2: Evolution of coupling constants (from left to right, and top to bottom): $y_1(\mu),\ y_2(\mu),\ y_3(\mu),\ x(\mu),\ u(\mu)$ and $z(\mu)$