Renormalizable toy model of massive spin two field and new bigravity
  In this paper, we propose a toy model of the renormalizable theory describing massive spin two field. Although the model is renormalizable, we show that the model contains ghost. The coupling of the theory with gravity can be regarded as a new kind of bimetric gravity or bigravity. We show that the massive spin two field plays the role of the cosmological constant. 
Yuichi Ohara, Satoshi Akagi, and Shin'ichi Nojiri
hep-th astro-ph.CO gr-qc