An Analytical Approach to Lattice Gauge-Higgs Models

We describe an application of the linear $\de$-expansion to the calculation of correlation functions in SU(2)-Higgs lattice gauge theory. A significant advantage of the technique is that an infinite volume lattice may be used, allowing the non-analyticity in certain observables at a phase transition to be observed directly. We illustrate the approach with a preliminary application to the 3D SU(2)-Higgs model, as the dimensionally reduced effective theory for the electroweak standard model at high temperature, and calculate certain gauge invariant observables near the phase boundaries.