Stabilizing the vacuum in the gauged chiral sigma model

The introduction of vector mesons as fundamental fields coupling to quarks can remove vacuum instabilities in a purely quark-scalar meson theory used to describe low and intermediate energy hadron physics. The requirement that there be no Landau ghost in the quark-scalar meson sector translates into an interesting restriction on the constituent quark mass, or in the case of a meson-nucleon theory on the nucleon mass. If these coupling constant constraints are satisfied the quark-scalar sector becomes asymptotically free. (orig.)