New mechanism for the generation of primordial seeds for the cosmic magnetic fields

We discuss the inflationary production of magnetic seeds for the galactic dynamo through the photon-graviphoton mixing typical of extended models of local supersymmetry. An analisys of the allowed region in parameter space shows that such a mechanism is compatible with existing phenomenological bounds on the vector mass and on the mixing parameter, but requires a large enough mixing that seems difficult to implement naturally in the context of a minimal supersymmetric scenario.