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.
