Vacuum Energy, Cosmological Supersymmetry Breaking and Inflation from Colliding Brane Worlds.

In the context of colliding brane worlds I discuss a toy cosmological model, developed in collaboration with E. Gravanis, which arguably produces inflation and a relaxing to zero cosmological "constant" hierarchically small as compared to the supersymmetry breaking (TeV) scale. Supersymmetry breaking is induced by compactification of the brane worlds on magnetized tori. The crucial ingredient is the non-criticality (non conformality) of string theory on the observable brane world induced at the collision, which is thus viewed as a cause for departure from equilibrium in this system. The hierarchical smallness of the present-era vacuum energy, as compared to the SUSY breaking scale, is thus attributed to relaxation.