Finite size scaling analysis of the Higgs mass bound in the O(4) approximation

Our finite size scaling analysis of the renormalized mass and renormalized vacuum expectation value in the broken symmetry phase of the O(4) model at infinite bare coupling is presented. We find that the Higgs loop contributions are important in the volume range where we did the simulations. The Goldstone wavefunction renormalization constant is measured to relate the bare vacuum expectation value of the Higgs field to the W boson mass. Our Monte Carlo data at λ0=∞ show that the SU(2) Higgs sector with spontaneously broken O(4) symmetry and perturbative gauge coupling is driven to a trivial Gaussian fixed point as criticality is approached. We find an upper bound mH ≅ 640 GeV on the Higgs mass at a dimensionless correlation length ξ=2 on the lattice. The bound will decrease logarithmically with increasing ξ. (orig.)