Brane oscillations and the cosmic coincidence problem

Abstract

We show that, under general assumptions, in six-dimensional brane-world models with compactified large extra dimensions, the energy density of brane oscillations scales as that of cold dark matter and its present value is compatible with observations. This value is obtained from the only dimensional scale in the theory, namely, the fundamental scale of gravity in six dimensions M(6)similar to1 TeV, without any fine-tuning or the introduction of additional mass scales apart from the large size of the extra dimensions. It has been suggested that the same kind of model could provide also the correct magnitude of the cosmological constant. This observation might be relevant for the resolution of the cosmic coincidence problem in the brane-world scenario.