The Family SU(2)_l x SU(2)_h x U(1) Model

TL;DR

This paper proposes an extension of the Standard Model with a family-dependent gauge symmetry, predicting new heavy gauge bosons and Higgs particles that could be detected at the LHC, and analyzes their phenomenology and compatibility with existing data.

Contribution

It introduces a novel family-dependent gauge extension of the Standard Model and explores its symmetry breaking and phenomenological implications.

Findings

Predicted nearly degenerate heavy W' and Z' bosons with non-universal couplings.

Extra Higgs bosons with masses in the TeV range.

Model consistent with electroweak precision data and testable at the LHC.

Abstract

We consider extension of the standard model $SU(2)_l \times SU(2)_h \times U(1)$ where the first two families of quarks and leptons transform according to the $SU(2)_l$ group and the third family according to the $SU(2)_h$ group. In this approach, the largeness of top-quark mass is associated with the large vacuum expectation value of the corresponding Higgs field. The model predicts almost degenerate heavy $W'$ and $Z'$ bosons with non-universal couplings, and extra Higgs bosons. We present in detail the symmetry breaking mechanism, and carry out the subsequent phenomenology of the gauge sector. We compare the model with electroweak precision data, and conclude that the extra gauge bosons and the Higgs bosons whose masses lie in the TeV range, can be discovered at the LHC.