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 $W^{\prime }$ and $Z^{\prime }$ bosons with nonuniversal 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.

• Received 15 November 2009

DOI:https://doi.org/10.1103/PhysRevD.81.015006