Bounds on the renormalized couplings in an SU(2)L ⊗ SU(2)R symmetric Yukawa model

Abstract The vacuum stability lower bound on the mass of the Higgs boson is numerically investigated in an SU(2) L ⊗ SU(2) R symmetric Yukawa model, which describes two heavy degenerate fermion doublets in the limit of vanishing gauge couplings. The values for the lower bound are in good agreement with those obtained from an integration of the one-loop β-functions, although the couplings are strong. The upper bound on the fermion mass and renormalized Yukawa coupling is also determined in the part of bare parameter space where reflection positivity has been proven.