Dynamics behind the quark mass hierarchy

TL;DR

This paper proposes a new class of models where the dynamics responsible for electroweak symmetry breaking naturally produce the observed quark mass hierarchy, involving composite Higgs bosons and flavor interactions without fine tuning.

Contribution

It introduces a novel framework linking electroweak symmetry breaking dynamics to quark mass generation, including a detailed model with a fourth family and composite Higgs bosons.

Findings

Realistic quark mass spectrum achieved without fine tuning

Presence of multiple composite Higgs bosons

Model includes a fourth quark family

Abstract

We introduce a new class of models describing the quark mass hierarchy. In this class, the dynamics primarily responsible for electroweak symmetry breaking (EWSB) leads to the mass spectrum of quarks with no (or weak) isospin violation. Moreover, the values of these masses are of the order of the observed masses of the down-type quarks. Then, strong (although subcritical) horizontal diagonal interactions for the $t$ quark plus horizontal flavor-changing neutral interactions between different families lead (with no fine tuning) to a realistic quark mass spectrum. In this scenario, many composite Higgs bosons occur. A concrete model with the dynamical EWSB with the fourth family is described in detail.