We study breaking and restoration of supersymmetry in five-dimensional
theories by determining the mass spectrum of fermions from their equations of
motion. Boundary conditions can be obtained from either the action principle by
extremizing an appropriate boundary action (interval approach) or by assigning
parities to the fields (orbifold approach). In the former, fields extend
continuously from the bulk to the boundaries, while in the latter the presence
of brane mass-terms cause fields to jump when one moves across the branes. We
compare the two approaches and in particular we carefully compute the
non-trivial jump profiles of the wavefunctions in the orbifold picture for very
general brane mass terms. We also include the effect of the Scherk-Schwarz
mechanism in either approach and point out that for a suitable tuning of the
boundary actions supersymmetry is present for arbitrary values of the
Scherk-Schwarz parameter. As an application of the interval formalism we
construct bulk and boundary actions for super Yang-Mills theory. Finally we
extend our results to the warped Randall-Sundrum background.Comment: 17 pages, v2: affiliations correcte
