New top-flavor models with seesaw mechanism

A new class of models is constructed in which the third family quarks, but not leptons, experience a new SU(2) or U(1) gauge force. Anomaly cancellation enforces the introduction of spectator quarks so that top and bottom quark masses are naturally generated via a seesaw mechanism. We find the new contributions to the (S,T,U) parameters and Zb(bar b)vertex to be generically small. We analyze how the reasonable flavor mixing pattern can be generated to ensure the top-seesaw mechanism and sufficiently suppress flavor-changing effects for light quarks. Collider signatures for the light Higgs boson and top quark are also discussed