INTERACTING MAJORANA FERMIONS AND COSMIC ACCELERATION

摘要

We consider the possibility that a simple system consisting of one species of Majorana fermion with a vacuum mass, m_O, interacting with a scalar field of mass, m_ζ, can be the source of repulsion in the Friedmann equation, leading to acceleration of the expansion of the Universe at particular epochs. We assume a very cold system, approximated by a degenerate Fermi gas. We examine numerical results appropriate to parameter ranges that would allow active neutrinos as candidate fermions, and show that this is an unlikely result. We then extend the parameter ranges to include the possibility that the fermion in question is the Lightest Supersymmetric Particle or a much lighter possible sterile neutrino and show that these possibilities survive.