Bounds on flavor gauge bosons from precision electroweak data

Abstract

Gauged flavor symmetries at low energies have been proposed in models of dynamical electroweak symmetry breaking and fermion mass generation. The massive flavor gauge bosons give rise to corrections to precisely measured electroweak quantities. We perform a fit to the collider electroweak data and place indirect limits on such new physics. In particular we study several models from the literature: universal coloron, chiral top color, chiral quark family symmetry, SU(9) and SU(12) chiral flavor symmetry. The $95%$ exclusion limits on the mass of the heavy gauge bosons for these models, at their critical coupling for chiral symmetry breaking, typically lie between 1 and 3 TeV. We discuss the robustness of these bounds with respect to changes in Higgs boson mass, b-quark asymmetry data, the SLD left right asymmetry data, or additional new physics.