PUB - Publikationen an der Universität Bielefeld

We study the O(4)-symmetric phi4-theory in the scaling region of the broken phase using the standard and a Symanzik improved action with infinite bare self-coupling lambda. A high precision Monte Carlo simulation is performed by applying the reflection cluster algorithm. Employing the histogram method we analytically continue to a sequence of values of the hopping parameter kappa neighbouring the actually simulated ones. In the investigated vicinity of the critical point kappa(c) finite volume effects affecting, e.g., the determination of the field expectation value SIGMA and the mass m(sigma) of the sigma-particle, are very well described by one-loop renormalized perturbation theory. We carry out a detailed scaling analysis on a high level of precision. Finally we discuss the upper bound on the Higgs mass for both kinds of actions.