  Theories beyond the Standard Model often contain mass scales hierarchically
different from the electroweak scale and the Planck scale. It has been shown
that such hierarchical mass scales can be realized as typical energy scales of
multiple 3-branes in a 5D warped spacetime. We present a mechanism for
stabilizing the intervals between the multiple 3-branes in the warped extra
dimension, by introducing a single 5D scalar field with brane-localized
potentials. We discuss the radion stabilization by solving the Einstein
equation and the scalar field equation of motion so that a backreaction effect
on the geometry due to the presence of the scalar field is taken into account.
Perturbations from the background configuration are then considered with proper
identification of multiple radion degrees of freedom. By solving their
equations of motion, we compute the mass spectrum of the radion-scalar field
system and the radion couplings to brane-localized matter fields, which are
found to be suppressed by typical energy scales and radion profiles at the
branes. We also compute the mass spectrum of Kaluza-Klein gravitons and their
profiles in the extra dimension. Some applications of the setup are briefly
described. Our analysis provides a solid ground to build 5D warped extra
dimension models with multiple 3-branes.
