  We propose a new unified model that describes~dark energy and dark matter in
the context of $f(R,\phi )$ gravity using a massive scalar field in five
dimensions. The scalar field is considered in the bulk that surrounds the
3-brane in branworld model. We show that for a specific choice of the $%
f(R,\phi )$ function, we can describe the Einstein gravitation in 4-dimensional
space-time. We obtain a relationship between the speed of the universe's
expansion and the speed of the bulk's expansion. We also propose that the dark
matter is represented by the scalar field mass and that the dark energy is a
kinetic energy of this field. Finally, we show that, according to conditions,
one can obtain the percentages of density\ of dark matter and the density of
ordinary matter.
