  We perform an explicit two-loop computation of the Higgs mass in a
five-dimensional supersymmetric theory compactified on the orbifold S^1/Z_2,
with superpotential localized on a fixed-point brane and supersymmetry broken
in the bulk of the extra dimension by Scherk-Schwarz boundary conditions. At
one-loop, the Higgs mass is finite and proportional to 1/R^2, R being the
radius of the extra dimension. The two-loop corrections contain finite
proportional to 1/R^2 and linearly divergent Lambda/R terms, where Lambda is
the cutoff of the five-dimensional theory. The divergent terms are cancelled by
diagrams containing one-loop wave-function renormalization counterterms, i.e.
by linear threshold effects of Yukawa (and gauge) couplings, at the scale 1/R.
As a result there is no counterterm for the Higgs mass, which is finite and
calculable to the considered order.

High Energy Physics - Phenomenology