  Supersymmetric theories in 5d orbifold can have Fayet-Iliopoulos (FI) terms
on the boundaries. These terms induce a 5d mass for the bulk matter fields. We
analyze this effect using N=1 superfields and show how it can be understood as
a mixing between the U(1) gauge boson and the graviphoton. We also study the
implications of the FI-terms in the mass spectrum of theories with
Scherk-Schwarz supersymmetry breaking. We present a new 5d supersymmetric model
that has the massless spectrum of the Standard Model and predicts a Higgs boson
with a mass around the present experimental limit.
