  In the standard model in universal extra dimensions (UED) the mass of the
Higgs field is driven to the cutoff of the higher-dimensional theory. This
re-introduces a small hierarchy since the compactification scale 1/R should not
be smaller than the weak scale. In this paper we study possible solutions to
this problem by considering five-dimensional theories where the Higgs field
potential vanishes at tree level due to a global symmetry. We consider two
avenues: a Little Higgs model and a Twin Higgs model. An obstacle for the
embedding of these four-dimensional models in five dimensions is that their
logarithmic sensitivity to the cutoff will result in linear divergences in the
higher dimensional theory. We show that, despite the increased cutoff
sensitivity of higher dimensional theories, it is possible to control the Higgs
mass in these two scenarios. For the Little Higgs model studied, the
phenomenology will be significantly different from the case of the standard
model in UED. This is due to the fact that the compactification scale
approximately coincides with the scale where the masses of the new states
appear. For the case of the Twin Higgs model, the compactification scale may be
considerably lower than the scale where the new states appear. If it is as low
as allowed by current limits, it would be possible to experimentally observe
the standard model Kaluza-Klein states as well as a new heavy quark. On the
other hand, if the compactification scale is higher, then the phenomenology at
colliders would coincide with the one for the standard model in UED.
