Lattice Gauge Theory Approach to Spontaneous Symmetry Breaking from an Extra Dimension

We present lattice simulation results corresponding to an SU(2) pure gauge theory defined on the orbifold space E_4 x I_1, where E_4 is the four-dimensional Euclidean space and I_1 is an interval, with the gauge symmetry broken to a U(1) subgroup at the two ends of the interval by appropriate boundary conditions. We demonstrate that the U(1) gauge boson acquires a mass from a Higgs mechanism. The mechanism is driven by two of the extra-dimensional components of the five-dimensional gauge field which play respectively the role of the longitudinal component of the gauge boson and a massive real physical scalar, the Higgs particle. Despite the non-renormalizable nature of the theory, we observe only a mild cut-off dependence of the physical observables. We also show evidence that there is a region in the parameter space where the system behaves in a way consistent with dimensional reduction.