Integral representation for vacuum polarization by fermions in uniform non-abelian gauge potentials

Previous calculations of vacuum polarization in constant SU(2) vector gauge potentials are extended by the derivation of a parametric integral representation for the vacuum polarization of spin-1/2 isospin-1/2 matter fields. Renormalization of the effective lagrangian is carried out to obtain a finite gauge-invariant result. Surfaces of singularity thresholds are derived which divide the space of potentials into domains of vacuum stability and domains of vacuum instability where the vauum decays by the production of particle-antiparticle pairs. (orig.)