Accelerating universe in brane gravity with a confining potential
  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. 
M. Heydari-Fard, M. Shirazi, S. Jalalzadeh and H. R. Sepangi