Supersymmetron

Abstract

We consider a supersymmetric model of dark energy coupled to cold dark matter: the supersymmetron. In the absence of cold dark matter, the supersymmetron converges to a supersymmetric minimum with a vanishing cosmological constant. When cold dark matter is present, the supersymmetron evolves to a matter dependent minimum where its energy density does not vanish. In the early Universe until the recent past of the Universe, the energy density of the supersymmetron is negligible compared to the cold dark matter energy density. Away from the supersymmetric minimum, the equation of state of the supersymmetron is constant and negative. When the supersymmetron reaches the neighbourhood of the supersymmetric minimum, its equation of state vanishes rapidly. This leads to an acceleration of the Universe which is transient unless supersymmetry breaking induces a pure cosmological constant and acceleration of the Universe does not end. Moreover, we find that the mass of supersymmetron is always greater than the gravitino mass. As a result, the supersymmetron generates a short ranged fifth force which evades gravitational tests. On the other hand, we find that the supersymmetron may lead to relevant effects on large scale structures.