ar X iv : g r - qc / 0 41 10 66 v 1 1 4 N ov 2 00 4 5 - dimensional Brans - Dicke Theory and Cosmic Acceleration

We consider a 5-dimensional scalar-tensor theory which is a direct generalization of the original 4-dimensional Brans-Dicke theory to 5-dimensions. By assuming that there is a hypersurface-orthogonal spacelike Killing vector field in the underlying 5-dimensional spacetime, the theory is reduced to a 4-dimensional theory where the 4-metric is coupled with two scalar fields. The cosmological implication of this reduced theory is then studied in the Robertson-Walker model. It turns out that the two scalar field may account naturally for the present accelerated expansion of our universe. PACS number(s): 04.50.+h, 98.80.Es