Five-dimensional massive vector fields and radion stabilization

We provide a description of the five-dimensional Higgs mechanism in supersymmetric gauge theories compactified on the orbifold S¹ /ℤ₂ by means of the N superfield formalism. Goldstone bosons absorbed by vector multiplets can come either from hypermultiplets or from gauge multiplets of opposite parity (Hosotani mechanism). Supersymmetry is broken by the Scherk-Schwarz mechanism. In the presence of massive hypermultiplets and gauge multiplets, with different supersymmetric masses, the radion can be stabilized with positive (de Sitter) vacuum energy. The masses of vector and hypermultiplets can be fine-tuned to have zero (Minkowski) vacuum energy.