  We construct the effective theory of the graviscalar radion in the
Randall-Sundrum scenario, taking into account effects arising from the
stabilization of the extra dimension through the Goldberger-Wise mechanism. We
explore the conditions under which the radion can remain light, and determine
the corrections to its couplings to Standard Model (SM) states when the effects
of stabilization are taken into account. We show that in the theories of
interest for electroweak symmetry breaking that have a holographic dual, the
presence of a light radion in the spectrum is not a robust prediction of the
framework, but is in fact associated with mild tuning. We find that corrections
to the form of the radion couplings to Standard Model particles arising from
effects associated with brane stabilization are suppressed by the square of the
ratio of the radion mass to the Kaluza-Klein scale. These corrections are small
in theories where the radion is light, and are generally subleading, except in
the case of couplings to the SM gluons and photon, when they can sometimes
dominate. The AdS/CFT correspondence relates the radion in Randall-Sundrum
models to the dilaton in theories where a strongly coupled conformal symmetry
is spontaneously broken. We show that the discrepancies in the literature
between the results for the dilaton and the radion can be traced to the
omission of self-interaction terms that would otherwise dominate the potential
for the Goldberger-Wise scalar near the infrared brane. In the dual picture,
this corresponds to neglecting the corrections to the scaling behavior of the
operator that breaks conformal symmetry when it grows large. With the inclusion
of these self-interaction terms, we find good agreement between the results on
the two sides of the correspondence.
