Fate of the standard model with a heavy Higgs particle

The breakdown of the standard electroweak model is investigated when the mass of the Higgs particle is comparable or larger than the weak interaction scale 1/√GF. The history of the problem is presented and theoretical motivations for an upper bound on the mass of the Higgs particle are discussed. For the non-perturbative study of the Higgs sector we describe a large scale computer simulation of the effective action. For illustration, a sample calculation will be presented in the scalar Φ4 model with spontaneous symmetry breaking. The Higgs sector with spontaneously broken O(4) symmetry is studied as a realistic application of the method. Our most important result is the determination of an upper bound MH ≅ 550 GeV on the mass of the Higgs particle with a momentum cut-off 5π times larger than the Higgs mass. (orig.)