We analyze the Scherk-Schwarz (SS) supersymmetry breaking in brane-world five
dimensional theories compactified on the orbifold S1/Z2. The SS
breaking parameter is undetermined at the tree-level (no-scale supergravity)
and can be interpreted as the Hosotani vacuum expectation value corresponding
to the U(1)R group in five dimensional N=2 (ungauged) supergravity. We show
that the SS breaking parameter is fixed at the loop level to either 0 or 1/2
depending on the matter content propagating in the bulk but in a rather
model-independent way. Supersymmetry breaking is therefore fixed through a
radiative Scherk-Schwarz mechanism. We also show that the two discrete values
of the SS parameter, as well as the supersymmetry breaking shift in the
spectrum of the bulk fields, are altered in the presence of a brane-localized
supersymmetry breaking arising from some hidden sector dynamics. The interplay
between the SS and the brane localized breaking is studied in detail.Comment: 16 pages, 2 figures, uses axodraw. References adde