A Three Higgs Doublet Model for the Fermion Mass Hierarchy Problem

TL;DR

This paper introduces a three Higgs doublet model incorporating a type-II seesaw mechanism and a new gauge symmetry to address the fermion mass hierarchy, with implications for dark matter detection.

Contribution

It presents a novel three Higgs doublet extension of the Standard Model integrating a type-II seesaw and a new gauge symmetry to explain fermion mass hierarchies.

Findings

Constraints from electroweak precision measurements are analyzed.

The model's dark matter candidate is studied for direct detection signatures.

Fermion Yukawa couplings are naturally suppressed except for the top quark.

Abstract

In this paper we propose a possible explanation to the Fermion mass hierarchy problem by fitting the type-II seesaw mechanism into the Higgs doublet sector, such that their vacuum expectation values are hierarchal. We extend the Standard Model with two extra Higgs doublets as well as a spontaneously broken $U_X(1)$ gauge symmetry. All the fermion Yukawa couplings except that of top quark are of order ${\cal O} (10^{-2})$ in our model. Constraints on the parameter space from Electroweak precision measurements are studied. Besides, the neutral component of the new fields, which are introduced to cancel the anomalies of the $U(1)_X$ gauge symmetry can be dark matter candidate. We investigate its signature in the dark matter direct detection.