  We construct the Einstein field equations on a 4-dimensional brane embedded
in an $m$-dimensional bulk where the matter fields are confined to the brane by
means of a confining potential. As a result, an extra term in the Friedmann
equation in a $m$-dimensional bulk appears that may be interpreted as the
X-matter, providing a possible phenomenological explanation for the
acceleration of the universe. The study of the relevant observational data
suggests good agreement with the predictions of this model.
