Stable cosmology in ghost-free quasidilaton theory
  We present a novel cosmological solution in the framework of extended
quasidilaton theory which underwent scrutiny recently. We only consider terms
that do not generate the Boulware-Deser degree of freedom, hence the
"ghost-free" quasidilaton theory, and show three new branches of cosmological
evolution therein. One of the solutions passes the perturbative stability
tests. This new solution exhibits a late time self-acceleration and all
graviton polarizations acquire masses that converge to a constant in the
asymptotic future. Moreover, all modes propagate at the speed of light. We
propose that this solution can be used as a benchmark model for future
phenomenological studies.
