Vertical mass hierarchy in the case study of a hybrid model

TL;DR

This paper investigates a hybrid model combining Technicolor and scalar fields to explain the vertical mass hierarchy in fermions, showing how scalar dynamics and radiative corrections contribute to mass generation.

Contribution

It introduces a model where scalar doublets explain fermion mass hierarchy without large Yukawa couplings, linking strong dynamics to scalar sector effects.

Findings

Scalar doublets provide a natural explanation for mass hierarchy.

Lepton and down quark masses are derived radiatively from quark masses.

Scalar masses are predicted to be large and universal.

Abstract

We study a hybrid model in which the Technicolor and fundamental heavy scalars live together. We concern extreme case, where electroweak symmetry breaking (EWSB) comes almost entirely from the strong dynamics of Technicolor, but the masses of the light fermions, e.g. leptons arises due to the weakly interacting scalars with one universal Yukawa interaction. We have found that SU(2) scalar two doublets, which are private but universal for each generation, offer a natural explanation of the vertical mass hierarchy. There is no large Yukawa coupling in the theory and the scalar masses are expected to be quite universal and large. The lepton mass hierarchy arises radiatively from the quark mass hierarchy, which is affected by the scalar sector as well. Lepton and down quark masses are calculated in a simplified case of neglected mixing.