Scalar perturbations from brane-world inflation with curvature effects
  We consider a generalization of the Randall-Sundrum single brane-world
scenario (RS2). More precisely, the generalization is described through
curvature corrections, corresponding to a Gauss-Bonnet term in the bulk and a
Hilbert-Einstein term, as well as the strength of the induced gravity term, on
the brane. We are mainly interested in analyzing the early inflationary era of
the brane, which we model within the extreme slow-roll limit, i.e., under a de
Sitter like brane inflation, where the inflaton field is confined on the brane.
We compute the scalar perturbations in this model and compare our results with
those previously obtained for the RS2 scenario with and without an induced
gravity term on the brane or a Gauss-Bonnet term in the bulk. The amplitude of
the scalar perturbations is decreased as compared with a pure RS2 model. In
addition, the effect from the Gauss-Bonnet correction in an induced gravity
brane-world model is to decrease the amplitude of the scalar perturbations, and
a similar result is obtained for the induced gravity effect in a Gauss-Bonnet
brane-world. In general, in the high energy limit the amplitude is highly
suppressed by the Gauss-Bonnet effect. Finally, we constrain the model using
the latest WMAP7 data.
