Toward Solving the Cosmological Constant Problem?
  We discuss the cosmological constant problem in the context of higher codimension brane world scenarios with infinite-volume extra dimensions. In particular, by adding higher curvature terms in the bulk action we are able to find smooth solutions with the property that the 4-dimensional part of the brane world-volume is flat for a range of positive values of the brane tension. 
Olindo Corradini, Alberto Iglesias and Zurab Kakushadze