hep-ph/9911406
Cosmology of Brane Models with Radion Stabilization
Authors: Csaba Csaki, Michael Graesser, Lisa Randall, John Terning
Journal-ref: Phys.Rev. D62 (2000) 045015
We analyze the cosmology of the Randall-Sundrum model and that of compact brane
models in general in the presence of a radius stabilization mechanism. We find
that the expansion of our universe is generically in agreement with the
expected effective four dimensional description. The constraint (which is
responsible for the appearance of non-conventional cosmologies in these models)
that must be imposed on the matter densities on the two branes in the theory
without a stabilized radius is a consequence of requiring a static solution
even in the absence of stabilization. Such constraints disappear in the
presence of a stablizing potential, and the ordinary FRW
(Friedmann-Robertson-Walker) equations are reproduced, with the expansion
driven by the sum of the physical values of the energy densities on the two
branes and in the bulk. For the case of the Randall-Sundrum model we examine
the kinematics of the radion field, and find that corrections to the standard
FRW equations are small for temperatures below the weak scale. We find that
the radion field has renormalizable and unsuppressed couplings to Standard
Model particles after electroweak symmetry breaking. These couplings may have
important implications for collider searches. We comment on the possibility
that matter off the TeV brane could serve as a dark matter candidate.