New symmetries in Fierz-Pauli massive gravity
  We expose a new symmetry for linear perturbations around a solution of non-linear Fierz-Pauli massive gravity plus a bare cosmological constant. The cosmological constant is chosen such that the background metric is flat while the Stuckelberg fields have a non-trivial profile. Around this background, at linear order the new symmetry reduces the propagating degrees of freedom to those of General Relativity, namely the massless helicity 2 modes only. We discuss the physical consequences and possible applications of these findings. 
Gianmassimo Tasinato, Kazuya Koyama, Gustavo Niz
hep-th astro-ph.CO hep-ph