Statistical Approach to the Cosmological-Constant Problem on Brane Worlds

Abstract

We investigate the physically accepted solutions of general Braneworld scenarios, scanning uniformly the associated parameter space. Without making any further assumptions we find that solutions which give "small" Hubble parameters on the physical brane, and therefore "small" effective cosmological constants on the 4D Universe, are far more probable than those with "large" ones. Eventually, their distribution tends to the $\delta$-function in the limit of continuous covering of the parameter space.