Hierarchical Quark and Lepton Masses with Sequential U(1) Gauge Symmetry

TL;DR

This paper proposes a model extending the Standard Model with an anomaly-free U(1)_X gauge symmetry, using minimal Higgs content to generate hierarchical quark and lepton masses and a viable neutrino mass matrix.

Contribution

It introduces a new sequential application of U(1)_X symmetry with minimal Higgs fields to explain fermion mass hierarchies and neutrino masses.

Findings

Hierarchical quark and lepton masses achieved

Viable seesaw neutrino mass matrix constructed

Model uses only one Higgs doublet and two U(1)_X singlets

Abstract

Instead of right-handed neutrino singlets, the standard model is extended to include lepton triplets $(\Sigma^+, \Sigma^0, \Sigma^-)$. Each quark and lepton family may now transform under an anomaly-free $U(1)_X$ gauge symmetry, known already for many years. A new sequential application is presented, using just the one Higgs doublet of the standard model, together with two $U(1)_X$ Higgs singlets. The resulting structure has hierarchical quark and lepton masses, as well as a viable seesaw neutrino mass matrix.